# Triangle Area Calculator

Published: 4/26/2021 Last updated: 2/17/2023

Triangles are some of the most fundamental shapes in mathematics. Whether you are a student just learning about geometry or a professional working with complex calculations, the ability to calculate the area of a triangle is an essential skill. In this article, we will explore the definition of a triangle, the formula for calculating its area, and some examples to help you better understand this concept. We will also answer some frequently asked questions about triangle area calculations.

## Definition of a Triangle

A triangle is a three-sided polygon with three angles. The sum of the angles in a triangle is always 180 degrees. Triangles can be classified based on the length of their sides and the measure of their angles. The three main types of triangles are:

• Equilateral triangle: all three sides are equal in length, and all three angles are 60 degrees.
• Isosceles triangle: two sides are equal in length, and two angles are equal in measure.
• Scalene triangle: no sides are equal in length, and no angles are equal in measure.

## Formula for Calculating Triangle Area

The formula for calculating the area of a triangle is:

Area = (base x height) / 2

The base of a triangle is the length of the side that is perpendicular to the height. The height of a triangle is the length of the line perpendicular to the base that goes through the opposite vertex. The area of a triangle is always half the product of its base and height.

## Examples of Calculating Triangle Area

Let's take a look at some examples to better understand how to calculate the area of a triangle using the formula we just discussed.

### Example 1

Find the area of an equilateral triangle with a side length of 5 units.

Solution:

Since an equilateral triangle has three equal sides, we know that each side of this triangle is 5 units in length. To find the height of the triangle, we can use the Pythagorean theorem, which tells us that the height is equal to the square root of 3 times the length of one of the sides divided by 2.

Height = √3/2 x 5 = 4.33 units (rounded to two decimal places)

Now we can use the formula to find the area:

Area = (base x height) / 2 = (5 x 4.33) / 2 = 10.83 square units

Therefore, the area of this equilateral triangle is 10.83 square units.

### Example 2

Find the area of an isosceles triangle with a base of 6 units and a height of 8 units.

Solution:

Since we know the base and height of this triangle, we can simply use the formula to find the area:

Area = (base x height) / 2 = (6 x 8) / 2 = 24 square units

Therefore, the area of this isosceles triangle is 24 square units.

### Example 3

Find the area of a scalene triangle with sides of length 7, 9, and 12 units.

Solution:

Since we have the lengths of all three sides of this triangle, we can use Heron's formula to find the area:

Area = √(s(s-a)(s-b)(s-c))

where s is the semiperimeter of the triangle (half the sum of the lengths of its three sides), and a, b, and c are the lengths of its sides.

Semiperimeter = (7 + 9 + 12) / 2 = 14

Area = √(14(14-7)(14-9)(14-12)) = √(14 x 7 x 5 x 2) = √980 = 31.24 square units (rounded to two decimal places)

Therefore, the area of this scalene triangle is 31.24 square units.

#### Q: What if I don't know the height of the triangle?

A: If you don't know the height of the triangle, you can use trigonometry to find it. For example, if you know the length of one side of the triangle and the angle it makes with the base, you can use the sine or cosine function to find the height.

#### Q: Can I use the formula to calculate the area of a right triangle?

A: Yes, you can. In a right triangle, the height is equal to one of the legs of the triangle, and the base is equal to the other leg. You can use the Pythagorean theorem to find the length of the missing side if necessary.

#### Q: Is the formula for calculating the area of a triangle the same for all types of triangles?

A: Yes, the formula is the same for all types of triangles, as long as you know the length of the base and the height.

## Conclusion

Calculating the area of a triangle is a fundamental skill in mathematics, and the formula for doing so is simple and straightforward. By knowing the length of the base and the height, you can quickly find the area of any type of triangle, whether it is equilateral, isosceles, or scalene. We hope this article has helped you better understand this important concept.

## References

We hope this article has been helpful in explaining how to calculate the area of a triangle using the length of its base and height. If you have any further questions or comments, please feel free to reach out to us. Thank you for reading!