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. As known, 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 you can use for all triangles, and it can answer the question of how 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. 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!

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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 your geometry studies, which deal with different structures and shapes, you are required to calculate areas and perimeters. As known, 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 you can use for all triangles, and it can answer your question about how 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 substitute the given values into the formula and we'll get:

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

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 #2

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

Exercise #3

Calculate the area of the following triangle:

444555AAABBBCCCEEE

Video Solution

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

Exercise #4

Calculate the area of the following triangle:

666777AAABBBCCCEEE

Video Solution

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

Exercise #5

What is the area of the triangle in the drawing?

5557778.68.68.6

Video Solution

Step-by-Step Solution

First, we will identify the data points we need to be able to find the area of the triangle.

the formula for the area of the triangle: height*opposite side / 2

Since it is a right triangle, we know that the straight sides are actually also the heights between each other, that is, the side that measures 5 and the side that measures 7.

We multiply the legs and divide by 2

5×72=352=17.5 \frac{5\times7}{2}=\frac{35}{2}=17.5

Answer

17.5

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