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

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

Examples with solutions for Area of a Trapezoid

Step-by-step solutions included
Exercise #1

Calculate the area of the trapezoid.

555141414666

Step-by-Step Solution

We use the formula (base+base) multiplied by the height and divided by 2.

Note that we are only provided with one base and it is not possible to determine the size of the other base.

Therefore, the area cannot be calculated.

Answer:

Cannot be calculated.

Video Solution
Exercise #2

Calculate the area of the trapezoid.

666777121212555

Step-by-Step Solution

To find the area of the trapezoid, we would ideally use the formula:

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

where b1b_1 and b2b_2 are the lengths of the two parallel sides and hh is the height. However, the given information is incomplete for these purposes.

The numbers provided (66, 77, 1212, and 55) do not clearly designate which are the bases and what is the height. Without this information, the dimensions cannot be definitively identified, making it impossible to calculate the area accurately.

Thus, the problem, based on the given diagram and information, cannot be solved for the area of the trapezoid.

Therefore, the correct answer is: It cannot be calculated.

Answer:

It cannot be calculated.

Video Solution
Exercise #3

Calculate the area of the trapezoid.

555888333

Step-by-Step Solution

To solve this problem, we'll calculate the area of the trapezoid using the standard formula:

  • Step 1: Identify the given dimensions:
  • Shorter base b1=5 b_1 = 5 .
  • Longer base b2=8 b_2 = 8 .
  • Height h=3 h = 3 .

Step 2: We apply the trapezoid area formula, which is:

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

Step 3: Substitute the given values into the formula:

A=12×(5+8)×3 A = \frac{1}{2} \times (5 + 8) \times 3 .

Step 4: Perform the calculations:

A=12×13×3 A = \frac{1}{2} \times 13 \times 3 .

A=12×39 A = \frac{1}{2} \times 39 .

A=19.5 A = 19.5 or 1912 19 \frac{1}{2} .

The area of the trapezoid is 1912 19 \frac{1}{2} .

Answer:

19 1/2

Video Solution
Exercise #4

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
Exercise #5

The trapezoid ABCD is shown below.

The height of ABCD is 6 cm.

The base BC is equal to 4 cm.

The base AD is equal to 8 cm.

Calculate the area of trapezoid ABCD.

444888666BBBCCCDDDAAAEEE

Step-by-Step Solution

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

  • Step 1: Identify the given information
  • Step 2: Apply the appropriate formula
  • Step 3: Perform the necessary calculations

Now, let's work through each step:

Step 1: The problem gives us the height of the trapezoid as 6cm6 \, \text{cm}, base BC as 4cm4 \, \text{cm} and base AD as 8cm8 \, \text{cm}.

Step 2: We'll use the formula for the area of a trapezoid:

A=12×(base1+base2)×height A = \frac{1}{2} \times (\text{base}_1 + \text{base}_2) \times \text{height}

Step 3: Substituting the given values into the formula:

A=12×(4+8)×6 A = \frac{1}{2} \times (4 + 8) \times 6

Calculating further,

A=12×12×6 A = \frac{1}{2} \times 12 \times 6

A=12×72 A = \frac{1}{2} \times 72

A=36cm2 A = 36 \, \text{cm}^2

Therefore, the area of the trapezoid ABCD is 36cm236 \, \text{cm}^2.

Answer:

36

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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