Area of Trapezoid Practice Problems & Formula Worksheets

Master trapezoid area calculations with step-by-step practice problems. Learn the formula, solve isosceles and rectangular trapezoids, and boost your geometry skills.

📚Master Trapezoid Area Calculations with Interactive Practice
  • Apply the trapezoid area formula: A = (base₁ + base₂) × height ÷ 2
  • Calculate areas of isosceles trapezoids with equal non-parallel sides
  • Solve rectangular trapezoid problems with perpendicular sides
  • Find missing dimensions using area and given measurements
  • Work backwards from area to determine unknown heights or bases
  • Practice real-world applications and complex multi-step problems

Understanding Area of a Trapezoid

Complete explanation with examples

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

Detailed explanation

Practice Area of a Trapezoid

Test your knowledge with 21 quizzes

Given the following trapezoid:

AAABBBCCCDDD5104

Calculate the area of the trapezoid ABCD.

Examples with solutions for Area of a Trapezoid

Step-by-step solutions included
Exercise #1

Given the trapezoid:

999121212555AAABBBCCCDDDEEE

What is the area?

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

Video Solution
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

Step-by-Step Solution

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

(Base+Base)h2=Area \frac{(Base+Base)\cdot h}{2}=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

Video Solution
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

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}

Video Solution
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

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

Video Solution
Exercise #5

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

777333AAABBBCCCDDDEEEFFF4

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

Video Solution

Frequently Asked Questions

What is the formula for finding the area of a trapezoid?

+
The area of a trapezoid is calculated using: A = (base₁ + base₂) × height ÷ 2. Add both parallel bases together, multiply by the perpendicular height, then divide by 2.

How do you find the area of an isosceles trapezoid?

+
Use the same formula: A = (base₁ + base₂) × height ÷ 2. In isosceles trapezoids, the non-parallel sides are equal, but this doesn't change the area calculation—you still only need the two bases and height.

What's the difference between trapezoid and parallelogram area formulas?

+
A trapezoid has one pair of parallel sides, so you add both bases: A = (base₁ + base₂) × height ÷ 2. A parallelogram has two pairs of parallel sides, so you use: A = base × height.

How do you find a missing trapezoid dimension when given the area?

+
Substitute known values into A = (base₁ + base₂) × height ÷ 2 and solve algebraically. For example, if area = 30, base₁ = 6, base₂ = 9, then: 30 = (6 + 9) × h ÷ 2, so h = 4.

What are the key properties of trapezoids I need to remember?

+
1. One pair of parallel sides (bases), 2. Height is perpendicular distance between bases, 3. Isosceles trapezoids have equal non-parallel sides, 4. Rectangular trapezoids have one right angle.

How many practice problems should I solve to master trapezoid areas?

+
Start with 10 basic problems to memorize the formula, then solve 15-20 varied problems including isosceles, rectangular, and missing dimension scenarios. Practice consistently rather than cramming.

What units should I use for trapezoid area answers?

+
Area is always expressed in square units (unit²). If dimensions are in centimeters, the area is in cm². If in feet, the area is in ft². Always include the squared unit in your final answer.

Can I use the trapezoid formula for other quadrilaterals?

+
The trapezoid formula works for any quadrilateral with one pair of parallel sides. It also works for rectangles and parallelograms (where both pairs are parallel), but simpler formulas exist for those shapes.

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