Area of a Triangle Practice Problems and Solutions

Master triangle area calculations with step-by-step practice problems. Learn formulas for right triangles, solve real-world examples, and build confidence.

📚Master Triangle Area Calculations with Interactive Practice
  • Calculate area of right triangles using the legs formula
  • Apply the base × height ÷ 2 formula for all triangle types
  • Solve complex problems involving perimeter and area relationships
  • Find missing measurements when area is given
  • Work with percentage-based triangle problems step-by-step
  • Identify and correct errors in triangle area calculations

Understanding Area of a right triangle

Complete explanation with examples

Formula to find the area of a right triangle

The area of a right triangle is an important subtopic that is repeated over and over again in exercises that include any right triangle.

It is calculated by multiplying the two sides that form the right angle (called legs) and dividing the result by 2.

A - area of a new right triangle

Detailed explanation

Practice Area of a right triangle

Test your knowledge with 27 quizzes

Calculate the area of the following triangle:

4.54.54.5777AAABBBCCCEEE

Examples with solutions for Area of a right triangle

Step-by-step solutions included
Exercise #1

Calculate the area of the right triangle below:

101010666888AAACCCBBB

Step-by-Step Solution

Due to the fact that AB is perpendicular to BC and forms a 90-degree angle,

it can be argued that AB is the height of the triangle.

Hence we can calculate the area as follows:

AB×BC2=8×62=482=24 \frac{AB\times BC}{2}=\frac{8\times6}{2}=\frac{48}{2}=24

Answer:

24 cm²

Video Solution
Exercise #2

Calculate the area of the triangle using the data in the figure below.

101010222AAABBBCCC

Step-by-Step Solution

To solve the problem of finding the area of triangle ABC \triangle ABC , we follow these steps:

  • Step 1: Identify the given measurements.
  • Step 2: Use the appropriate formula for the area of a triangle.
  • Step 3: Calculate the area using these measurements.

Let's go through each step in detail:
Step 1: From the figure, the base AB=10 AB = 10 and height AC=2 AC = 2 .
Step 2: The formula for the area of a triangle is: Area=12×base×height \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} .
Step 3: Substituting the known values into the formula, we get:

Area=12×10×2=12×20=10 \text{Area} = \frac{1}{2} \times 10 \times 2 = \frac{1}{2} \times 20 = 10

Therefore, the area of triangle ABC \triangle ABC is 10.

Answer:

10

Video Solution
Exercise #3

Calculate the area of the triangle below, if possible.

7.67.67.6444

Step-by-Step Solution

To solve this problem, we begin by analyzing the given triangle in the diagram:

While the triangle graphic suggests some line segments labeled with the values "7.6" and "4", it does not confirm these as directly usable as pure base or height without additional proven inter-contextual relationships establishing perpendicularity or side/unit equivalences.

Without a clear base and perpendicular height value, we cannot apply the triangle's area formula Area=12×base×height \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} effectively, nor do we have all side lengths for Heron's formula.

Therefore, due to insufficient information that specifically identifies necessary dimensions for area calculations such as clear height to a base or all sides' measures, the area of this triangle cannot be calculated.

The correct answer to the problem, based on insufficient explicit calculable details, is: It cannot be calculated.

Answer:

It cannot be calculated.

Video Solution
Exercise #4

Calculate the area of the triangle below, if possible.

8.58.58.5777

Step-by-Step Solution

The formula to calculate the area of a triangle is:

(side * height corresponding to the side) / 2

Note that in the triangle provided to us, we have the length of the side but not the height.

That is, we do not have enough data to perform the calculation.

Answer:

Cannot be calculated

Video Solution
Exercise #5

Calculate the area of the following triangle:

666777AAABBBCCCEEE

Step-by-Step Solution

The formula for the area of a triangle is

A=hbase2 A = \frac{h\cdot base}{2}

Let's insert the available data into the formula:

(7*6)/2 =

42/2 =

21

Answer:

21

Video Solution

Frequently Asked Questions

What is the formula for finding the area of a right triangle?

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The area of a right triangle is calculated by multiplying the two legs (sides that form the right angle) and dividing by 2. The formula is: Area = (leg₁ × leg₂) ÷ 2.

How do you find the area of a triangle when you know the base and height?

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Use the formula Area = (base × height) ÷ 2. The height must be perpendicular to the base. This formula works for all triangles, not just right triangles.

Can you find a missing leg length if you know the area and one leg of a right triangle?

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Yes, rearrange the area formula to solve for the unknown leg. If Area = (leg₁ × leg₂) ÷ 2, then unknown leg = (2 × Area) ÷ known leg.

What are the most common mistakes when calculating triangle area?

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Common errors include: 1) Forgetting to divide by 2, 2) Using the hypotenuse instead of legs in right triangles, 3) Not ensuring the height is perpendicular to the base, 4) Mixing up units in the final answer.

How do you solve triangle area problems with percentages?

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Convert percentages to decimals first, then apply them to find new measurements. For example, if one leg is 33⅓% greater than another, multiply the original by 1.333 to find the new length.

What units should I use for triangle area answers?

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Area is always measured in square units (cm², m², in², etc.). If the sides are given in centimeters, the area will be in square centimeters (cm²).

How do you check if your triangle area calculation is correct?

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Verify by: 1) Double-checking your multiplication and division, 2) Ensuring you used the correct measurements, 3) Confirming your answer has square units, 4) Using an alternative method if possible.

Can the same triangle have different area calculations depending on which side is the base?

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No, a triangle has only one area value. However, you can use different base-height combinations that will give the same result when calculated correctly using Area = (base × height) ÷ 2.

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