To find the area of a trapezoid, you need the following three pieces of information:

  • The length of base one
  • The length of base two
  • The height between the two bases

The formula to find the area of a trapezoid is as follows:

The sum of the bases multiplied by the height and then divided by two.

Formula of the trapezoid:

A=(Base 1+Base 2)×Height2 A=\frac{(Base~1+Base~2)\times Height}{2}

A7 - Trapezoid area formula

Practice Area of a Trapezoid

Examples with solutions for Area of a Trapezoid

Exercise #1

Given the trapezoid:

999121212555AAABBBCCCDDDEEE

What is the area?

Video Solution

Step-by-Step Solution

Formula for the area of a trapezoid:

(base+base)2×altura \frac{(base+base)}{2}\times altura

We substitute the data into the formula and solve:

9+122×5=212×5=1052=52.5 \frac{9+12}{2}\times5=\frac{21}{2}\times5=\frac{105}{2}=52.5

Answer

52.5

Exercise #2

The trapezoid ABCD is shown below.

Base AB = 6 cm

Base DC = 10 cm

Height (h) = 5 cm

Calculate the area of the trapezoid.

666101010h=5h=5h=5AAABBBCCCDDD

Video Solution

Step-by-Step Solution

First, we need to remind ourselves of how to work out the area of a trapezoid:

Formula for calculating trapezoid area

Now let's substitute the given data into the formula:

(10+6)*5 =
2

Let's start with the upper part of the equation:

16*5 = 80

80/2 = 40

Answer

40 cm²

Exercise #3

The trapezoid ABCD is shown below.

AB = 2.5 cm

DC = 4 cm

Height (h) = 6 cm

Calculate the area of the trapezoid.

2.52.52.5444h=6h=6h=6AAABBBCCCDDD

Video Solution

Step-by-Step Solution

First, let's remind ourselves of the formula for the area of a trapezoid:

A=(Base + Base) h2 A=\frac{\left(Base\text{ }+\text{ Base}\right)\text{ h}}{2}

We substitute the given values into the formula:

(2.5+4)*6 =
6.5*6=
39/2 = 
19.5

Answer

1912 19\frac{1}{2}

Exercise #4

The trapezoid ABCD is shown below.

AB = 5 cm

DC = 9 cm

Height (h) = 7 cm

Calculate the area of the trapezoid.

555999h=7h=7h=7AAABBBCCCDDD

Video Solution

Step-by-Step Solution

The formula for the area of a trapezoid is:

Area=12×(Base1+Base2)×Height \text{Area} = \frac{1}{2} \times (\text{Base}_1 + \text{Base}_2) \times \text{Height}

We are given the following dimensions:

  • Base AB=5AB = 5 cm
  • Base DC=9DC = 9 cm
  • Height h=7h = 7 cm

Substituting these values into the formula, we have:

Area=12×(5+9)×7 \text{Area} = \frac{1}{2} \times (5 + 9) \times 7

First, add the lengths of the bases:

5+9=14 5 + 9 = 14

Now substitute back into the formula:

Area=12×14×7 \text{Area} = \frac{1}{2} \times 14 \times 7

Calculate the multiplication:

12×14=7 \frac{1}{2} \times 14 = 7

Then multiply by the height:

7×7=49 7 \times 7 = 49

Thus, the area of the trapezoid is 49 cm2^2.

Answer

49 cm

Exercise #5

What is the area of the trapezoid in the diagram below?

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Video Solution

Step-by-Step Solution

To determine the area of the trapezoid, we will follow these steps:

  • Step 1: Identify the provided dimensions of the trapezoid.
  • Step 2: Apply the formula for the area of a trapezoid.
  • Step 3: Perform the arithmetic to calculate the area.

Let's proceed through these steps:

Step 1: Identify the dimensions
The given dimensions from the diagram are:
Height h=3 h = 3 cm.
One base b1=4 b_1 = 4 cm.
The other base b2=7 b_2 = 7 cm.

Step 2: Apply the area formula
To find the area A A of the trapezoid, use the formula:
A=12×(b1+b2)×h A = \frac{1}{2} \times (b_1 + b_2) \times h

Step 3: Calculation
Substituting the known values into the formula:
A=12×(4+7)×3 A = \frac{1}{2} \times (4 + 7) \times 3

Simplify the expression:
A=12×11×3 A = \frac{1}{2} \times 11 \times 3

Calculate the result:
A=12×33=332=16.5 A = \frac{1}{2} \times 33 = \frac{33}{2} = 16.5 cm²

The area of the trapezoid is therefore 16.5 16.5 cm².

Given the choices, this corresponds to choice : 16.5 16.5 cm².

Therefore, the correct solution to the problem is 16.5 16.5 cm².

Answer

16.5 16.5 cm²

Exercise #6

What is the area of the trapezoid in the diagram?

555138

Video Solution

Step-by-Step Solution

To find the area of the trapezoid, we will follow these steps:

  • Step 1: Identify the given dimensions of the trapezoid.
  • Step 2: Apply the area formula for a trapezoid using these dimensions.
  • Step 3: Perform the calculation to determine the area.

Let's work through each step more clearly:
Step 1: From the problem, we identify that the trapezoid has one base b1=13b_1 = 13 units, another base b2=8b_2 = 8 units, and its height h=5h = 5 units.
Step 2: The formula for the area of a trapezoid is:

A=12×(b1+b2)×h A = \frac{1}{2} \times (b_1 + b_2) \times h

Step 3: Substitute the values into the formula:

A=12×(13+8)×5 A = \frac{1}{2} \times (13 + 8) \times 5

A=12×21×5 A = \frac{1}{2} \times 21 \times 5

A=12×105 A = \frac{1}{2} \times 105

A=52.5units2 A = 52.5 \, \text{units}^2

Therefore, the area of the trapezoid is 52.5units2 52.5 \, \text{units}^2 .

Answer

52.5 52.5 cm²

Exercise #7

What is the area of the trapezoid in the figure?

777151515222AAABBBCCCDDDEEE

Video Solution

Step-by-Step Solution

We use the following formula to calculate the area of a trapezoid: (base+base) multiplied by the height divided by 2:

(AB+DC)×BE2 \frac{(AB+DC)\times BE}{2}

(7+15)×22=22×22=442=22 \frac{(7+15)\times2}{2}=\frac{22\times2}{2}=\frac{44}{2}=22

Answer

22 22 cm².

Exercise #8

What is the area of the trapezoid in the figure?

666777121212555444

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify the given information relevant to the trapezoid.
  • Step 2: Apply the appropriate formula for the area of a trapezoid.
  • Step 3: Perform the necessary calculations to find the area.

Now, let's work through each step:
Step 1: The problem gives us two bases, b1=6 b_1 = 6 cm and b2=12 b_2 = 12 cm, and a height h=4 h = 4 cm.
Step 2: We'll use the formula for the area of a trapezoid: A=12(b1+b2)h A = \frac{1}{2} \cdot (b_1 + b_2) \cdot h
Step 3: Substituting in the given values: A=12(6+12)4=12184=722=36 cm2 A = \frac{1}{2} \cdot (6 + 12) \cdot 4 = \frac{1}{2} \cdot 18 \cdot 4 = \frac{72}{2} = 36 \text{ cm}^2

Therefore, the solution to the problem is 36 36 cm².

Answer

36 36 cm².

Exercise #9

What is the area of the trapezoid in the figure?

6.56.56.5101010444AAABBBCCCDDDEEE

Video Solution

Step-by-Step Solution

To solve this problem, we'll compute the area of the trapezoid using the given dimensions and the area formula:

  • Step 1: Identify the given dimensions:
    • Base b1=10 b_1 = 10 cm
    • Base b2=6.5 b_2 = 6.5 cm
    • Height h=4 h = 4 cm
  • Step 2: Use the trapezoid area formula:
  • The formula for the area of a trapezoid is A=12(b1+b2)h A = \frac{1}{2}(b_1 + b_2)h .

  • Step 3: Substitute the given values into the formula:
  • A=12(10+6.5)×4 A = \frac{1}{2}(10 + 6.5) \times 4

  • Step 4: Calculate the area:
  • First, calculate the sum of the bases: 10+6.5=16.5 10 + 6.5 = 16.5 .

    Next, multiply by the height: 16.5×4=66 16.5 \times 4 = 66 .

    Finally, divide by 2 to get the area: 662=33\frac{66}{2} = 33 cm².

Therefore, the area of the trapezoid is 33 33 cm².

Answer

33 33 cm².

Exercise #10

Given the following trapezoid:

AAABBBCCCDDD584

Calculate the area of the trapezoid ABCD.

Video Solution

Step-by-Step Solution

To solve this problem, we follow these steps:

  • Step 1: Identify the given dimensions of the trapezoid.
  • Step 2: Use the formula for the area of a trapezoid.
  • Step 3: Substitute the given values into the formula and calculate the area.

Now, let's work through these steps:

Step 1: We know from the problem that trapezoid ABCD has bases AB=5 AB = 5 and CD=8 CD = 8 , with a height of AD=4 AD = 4 .

Step 2: The formula for the area of a trapezoid is:
A=12×(b1+b2)×h A = \frac{1}{2} \times (b_1 + b_2) \times h

Step 3: Plugging in the values:
A=12×(5+8)×4=12×13×4=522=26 A = \frac{1}{2} \times (5 + 8) \times 4 = \frac{1}{2} \times 13 \times 4 = \frac{52}{2} = 26

Therefore, the area of the trapezoid ABCD is 26 26 .

Answer

26

Exercise #11

Given the following trapezoid:

AAABBBCCCDDD795

Calculate the area of the trapezoid ABCD.

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify the lengths of the trapezoid's bases: AB=7 AB = 7 and CD=9 CD = 9 .
  • Step 2: Identify the height of the trapezoid: AD=5 AD = 5 .
  • Step 3: Apply the trapezoid area formula: A=12×(b1+b2)×h A = \frac{1}{2} \times (b_1 + b_2) \times h .
  • Step 4: Calculate the area using the values from Steps 1 and 2.

Now, let us work through each step:
Step 1: The length of base AB AB is (b1=7)(b_1 = 7) units, and the length of base CD CD is (b2=9)(b_2 = 9) units.
Step 2: The height AD AD is (h=5)(h = 5) units.

Step 3: Substitute the known values into the formula for the area of a trapezoid:
A=12×(7+9)×5 A = \frac{1}{2} \times (7 + 9) \times 5

Step 4: Calculate the results:
A=12×16×5=12×80=40 A = \frac{1}{2} \times 16 \times 5 = \frac{1}{2} \times 80 = 40

Therefore, the area of trapezoid ABCD is 40\mathbf{40} square units.

Answer

40

Exercise #12

Given the following trapezoid:

AAABBBCCCDDD683

Calculate the area of the trapezoid ABCD.

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Recall the formula for the area of a trapezoid.
  • Step 2: Substitute the given values into the formula.
  • Step 3: Calculate the area using arithmetic operations.

Let's work through each step:
Step 1: The formula for the area of a trapezoid is given by:
Area=12×(Base1+Base2)×Height \text{Area} = \frac{1}{2} \times (\text{Base}_1 + \text{Base}_2) \times \text{Height}
Step 2: Plug in the values: Base1=AB=6\text{Base}_1 = AB = 6, Base2=CD=8\text{Base}_2 = CD = 8, and the height AD=3AD = 3.
Area=12×(6+8)×3 \text{Area} = \frac{1}{2} \times (6 + 8) \times 3
Step 3: Perform the calculations:
Area=12×14×3=12×42=21 \text{Area} = \frac{1}{2} \times 14 \times 3 = \frac{1}{2} \times 42 = 21

Therefore, the area of trapezoid ABCDABCD is 2121.

Answer

21

Exercise #13

Given the following trapezoid:

AAABBBCCCDDD5104

Calculate the area of the trapezoid ABCD.

Video Solution

Step-by-Step Solution

To solve this problem, we'll calculate the area of trapezoid ABCD using the appropriate formula.

The formula for the area A A of a trapezoid is given by:

A=12×(Base1+Base2)×Height A = \frac{1}{2} \times (\text{Base}_1 + \text{Base}_2) \times \text{Height}

Substituting the given values into the formula, we have:

A=12×(5+10)×4 A = \frac{1}{2} \times (5 + 10) \times 4

First, calculate the sum of the bases:

5+10=15 5 + 10 = 15

Multiply by the height, and then take half:

A=12×15×4=12×60=30 A = \frac{1}{2} \times 15 \times 4 = \frac{1}{2} \times 60 = 30

Therefore, the area of the trapezoid ABCD is 30 square units.

Answer

30

Exercise #14

Given the following trapezoid:

AAABBBCCCDDD7115

Calculate the area of the trapezoid ABCD.

Video Solution

Step-by-Step Solution

To calculate the area of the trapezoid ABCD, we will follow these steps:

Given:

  • Base AB=7 AB = 7
  • Base CD=11 CD = 11
  • Height =5 = 5

Apply the trapezoid area formula:

The formula for the area of a trapezoid is:

A=12×(Base1+Base2)×Height A = \frac{1}{2} \times (\text{Base}_1 + \text{Base}_2) \times \text{Height}

Substitute the values into the formula:

A=12×(7+11)×5 A = \frac{1}{2} \times (7 + 11) \times 5

Simplify the expression:

A=12×18×5 A = \frac{1}{2} \times 18 \times 5

Calculate:

A=12×90 A = \frac{1}{2} \times 90

Finally, compute the area:

A=45 A = 45

Thus, the area of trapezoid ABCD is 45 45 .

Answer

45

Exercise #15

What is the area of the trapezoid ABCD?

999121212555AAABBBCCCDDDEEE

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Identify the given measurements: the lengths of the parallel sides (bases) and the height.
  • Use the trapezoid area formula to calculate the area.
  • Perform the necessary arithmetic to find the numerical answer.

Now, let's work through each step:
Step 1: The given measurements are Base1=9 \text{Base}_1 = 9 , Base2=12 \text{Base}_2 = 12 , and the height = 5.
Step 2: The formula for the area of a trapezoid is Area=12×(Base1+Base2)×Height \text{Area} = \frac{1}{2} \times (\text{Base}_1 + \text{Base}_2) \times \text{Height} .
Step 3: Substituting the numbers into the formula, we have:
Area=12×(9+12)×5 \text{Area} = \frac{1}{2} \times (9 + 12) \times 5

Calculating inside the parentheses first:
9+12=21 9 + 12 = 21

Then multiply by the height:
21×5=105 21 \times 5 = 105

Finally, multiply by one-half:
12×105=52.5 \frac{1}{2} \times 105 = 52.5

Therefore, the area of trapezoid ABCD ABCD is 52.5 52.5 .

Answer

52.5