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:

AAABBBCCCDDD795

Calculate the area of the trapezoid ABCD.

Examples with solutions for Area of a Trapezoid

Step-by-step solutions included
Exercise #1

What is the area of the trapezoid in the figure?

666777121212555444

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.

Video Solution
Exercise #2

Given the following trapezoid:

AAABBBCCCDDD7115

Calculate the area of the trapezoid ABCD.

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

Video Solution
Exercise #3

Given the following trapezoid:

AAABBBCCCDDD5104

Calculate the area of the trapezoid ABCD.

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

Video Solution
Exercise #4

Given the following trapezoid:

AAABBBCCCDDD584

Calculate the area of the trapezoid ABCD.

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

Video Solution
Exercise #5

What is the area of the trapezoid ABCD?

999121212555AAABBBCCCDDDEEE

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

Video Solution

Frequently Asked Questions

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

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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?

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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?

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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?

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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?

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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?

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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?

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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?

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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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