Area of Triangle Practice Problems - Scalene, Right & Obtuse

Master triangle area calculations with step-by-step practice problems covering scalene, right, and obtuse triangles using base-height formulas and real examples.

📚Master Triangle Area Calculations Through Interactive Practice
  • Calculate area of scalene triangles using base and height measurements
  • Apply the right triangle area formula with perpendicular legs
  • Solve obtuse triangle problems with external height projections
  • Identify corresponding base-height pairs for accurate calculations
  • Practice with real measurements and step-by-step solutions
  • Master the fundamental Area = (base × height) ÷ 2 formula

Understanding Area of a Scalene Triangle

Complete explanation with examples

Area of a scalene triangle

Formula to calculate the area of a scalene triangle:

B1  - Area of the scalene triangle

Detailed explanation

Practice Area of a Scalene Triangle

Test your knowledge with 27 quizzes

Calculate the area of the triangle below, if possible.

8.68.68.6777555

Examples with solutions for Area of a Scalene Triangle

Step-by-step solutions included
Exercise #1

Complete the sentence:

To find the area of a right triangle, one must multiply ________________ by each other and divide by 2.

Step-by-Step Solution

To solve this problem, begin by identifying the elements involved in calculating the area of a right triangle. In a right triangle, the two sides that form the right angle are known as the legs. These legs act as the base and height of the triangle.

The formula for the area of a triangle is given by:

A=12×base×height A = \frac{1}{2} \times \text{base} \times \text{height}

In the case of a right triangle, the base and height are the two legs. Therefore, the process of finding the area involves multiplying the lengths of the two legs together and then dividing the product by 2.

Based on this analysis, the correct way to complete the sentence in the problem is:

To find the area of a right triangle, one must multiply the two legs by each other and divide by 2.

Answer:

the two legs

Exercise #2

Calculate the area of the following triangle:

444555AAABBBCCCEEE

Step-by-Step Solution

The formula for calculating the area of a triangle is:

(the side * the height from the side down to the base) /2

That is:

BC×AE2 \frac{BC\times AE}{2}

We insert the existing data as shown below:

4×52=202=10 \frac{4\times5}{2}=\frac{20}{2}=10

Answer:

10

Video Solution
Exercise #3

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 #4

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

444777AAABBBCCC8.06

Step-by-Step Solution

To solve for the area of a triangle when the base and height are given, we'll use the formula:

Area=12×base×height \text{Area} = \frac{1}{2} \times \text{base} \times \text{height}

Given:

  • Base = 44 units

  • Height = 77 units

Apply the formula:

Area=12×4×7=12×28=14 \begin{aligned} \text{Area} &= \frac{1}{2} \times 4 \times 7 \\ &= \frac{1}{2} \times 28 \\ &= 14 \end{aligned}

Thus, the area of the triangle is 1414 square units.

Answer:

14

Video Solution
Exercise #5

Calculate the area of the following triangle:

4.54.54.5777AAABBBCCCEEE

Step-by-Step Solution

To find the area of the triangle, we will use the formula for the area of a triangle:

Area=12×base×height \text{Area} = \frac{1}{2} \times \text{base} \times \text{height}

From the problem:

  • The length of the base BC BC is given as 7 units.
  • The height from point A A perpendicular to the base BC BC is given as 4.5 units.

Substitute the given values into the area formula:

Area=12×7×4.5 \text{Area} = \frac{1}{2} \times 7 \times 4.5

Calculate the expression step-by-step:

Area=12×31.5 \text{Area} = \frac{1}{2} \times 31.5

Area=15.75 \text{Area} = 15.75

Therefore, the area of the triangle is 15.75 15.75 square units. This corresponds to the given choice: 15.75 15.75 .

Answer:

15.75

Video Solution

Frequently Asked Questions

What is the formula for calculating the area of any triangle?

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The universal triangle area formula is Area = (base × height) ÷ 2. The key is ensuring the height is perpendicular to the chosen base, forming a 90° angle.

How do you find the area of a scalene triangle?

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For scalene triangles, use Area = (base × height) ÷ 2. Identify any side as the base, then find the perpendicular height to that base. Multiply base by height, then divide by 2.

What makes calculating right triangle area easier?

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In right triangles, the two perpendicular sides (legs) can serve as base and height directly. Simply multiply the two legs and divide by 2: Area = (leg₁ × leg₂) ÷ 2.

How do you calculate obtuse triangle area when height is outside?

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When the height falls outside an obtuse triangle: 1) Use the actual triangle side length (not the extended line), 2) Use the given perpendicular height, 3) Apply the standard formula Area = (base × height) ÷ 2.

What are common mistakes when calculating triangle area?

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Common errors include: using non-corresponding base-height pairs, measuring slanted sides instead of perpendicular height, forgetting to divide by 2, and using extended lines instead of actual triangle sides in obtuse triangles.

Can you use any side as the base in triangle area calculations?

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Yes, any side can serve as the base. However, you must use the height that is perpendicular to your chosen base. Different base-height combinations will give the same area result.

What units should triangle area answers include?

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Triangle area is always expressed in square units (cm², m², in², etc.). If the measurements are in centimeters, the area will be in square centimeters (cm²).

How do you identify the correct height for each triangle type?

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For right triangles: use the two perpendicular sides. For acute triangles: height is inside the triangle. For obtuse triangles: height may extend outside, but always forms a 90° angle with the base when extended.

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