How to calculate the area of a triangle using trigonometry?

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How to calculate the area of a triangle using trigonometry?

Throughout geometry studies, which deal with various structures and shapes, you are required to calculate areas and perimeters. Each shape or structure has a different formula through which you can answer the question and calculate the area. Fortunately, there is one formula that can be applied to all triangles, and it can be used to calculate the area of a triangle using trigonometry.

In the field of mathematics, emphasis is also placed on trigonometry, which deals with the study of triangles, their angles, and sides. Every student is required to demonstrate knowledge of triangles (from right triangles to isosceles triangles), and thus also answer the question of how to calculate the area of a triangle using trigonometry.

One formula for all different triangles

Now that you know the formula for calculating the area of a triangle using trigonometry, you can use it in any question where you need to calculate areas in triangles. The formula for calculating the triangle:

Diagram of a triangle labeled ABC with sides AB = 5, AC = 8, and angle Y = 60°. The area formula  𝑆 𝐴𝐵𝐶 = (𝐴𝐵⋅𝐴𝐶⋅sin𝛾)/2 is shown.

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Test yourself on area of a triangle!

Complete the sentence:

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

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How to calculate triangle area using trigonometry?

Throughout geometry studies, which deal with different structures and shapes, you are required to calculate areas and perimeters. Each shape or structure has a different formula through which you can answer the question and calculate the area. Fortunately, there is one formula that can be applied to all triangles. It can be used to calculate the area of a triangle using trigonometry.

In mathematics studies, emphasis is also placed on trigonometry, which deals with the study of triangles, their angles and sides. Both students studying in level B math in middle school, and those who take 3 units in high school, are required to demonstrate knowledge of triangles (from right triangles to isosceles triangles), and thus also answer the question of how to calculate the area of a triangle using trigonometry.

One formula for all different triangles

Now that you know the formula for calculating the area of a triangle using trigonometry, you can use it in any question where you need to calculate areas in triangles. The formula for calculating the triangle:

Diagram of a triangle labeled ABC with sides AB = 5, AC = 8, and angle Y = 60°. The area formula  𝑆 𝐴𝐵𝐶 = (𝐴𝐵⋅𝐴𝐶⋅sin𝛾)/2 is shown.

Example:

Given triangle ABCABC and it is known that:

Side ABAB equals 55

Side ACAC equals 88

Angle YY is 6060 degrees.

Let's insert the given values into the formula and we should obtain:

s=ACABsin602s =\frac {AC \cdot AB \cdot \sin60} {2}

In other words:

s=580.8662s =\frac {5\cdot 8\cdot 0.866} {2}

The result obtained is: 17.3217.32.

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Examples with solutions for Area of a Triangle

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 right triangle below:

101010666888AAACCCBBB

Video Solution

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

Exercise #3

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

101010222AAABBBCCC

Video Solution

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

Exercise #4

Calculate the area of the triangle below, if possible.

7.67.67.6444

Video Solution

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.

Exercise #5

Calculate the area of the triangle below, if possible.

8.58.58.5777

Video Solution

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

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