4 Ways to Find the Height of a Triangle

A triangle is a versatile geometric shape with a variety of applications in mathematics, engineering, and daily life. One of the essential elements for calculating its area or solving other related problems is the height of a triangle. In this article, we will explore four different methods to find the height of a triangle.
1. Base and Area Method
When you have both the base and area of a triangle, it’s straightforward to find its height. The formula for finding the area of a triangle is:
Area = (Base * Height) / 2
Rearranging this formula to find the height:
Height = (2 * Area) / Base
Simply plug in the given values for base and area into this formula to obtain the height.
2. Trigonometry Method
If you know one angle between the base and height (apart from the 90° angle) and one side length, you can use trigonometry functions such as sine, cosine, or tangent to find missing side lengths, including the height. For instance:
Height = Side Length * sin(Angle)
or
Height = Side Length / tan(Angle)
By calculating these trigonometric functions with your known measurements, you can derive the height of your triangle.
3. Pythagorean Theorem Method
The Pythagorean theorem method applies to right triangles only. A right triangle has one internal angle equal to 90° and features a side called the hypotenuse opposite this 90° angle. The Pythagorean theorem states that:
Hypotenuse² = Base² + Height²
To find the height from this equation:
Height = √(Hypotenuse² – Base²)
If you know both sides adjacent to the right angle – namely, base and hypotenuse – plug these values into this formula to determine the height.
4. Heron’s Formula
Heron’s formula can be handy when you’re working with triangles in which the height is not perpendicular to the base. In this case, you’ll need three side lengths (a, b, and c) and the area of the triangle. Compute the semi-perimeter, s:
s = (a + b + c) / 2
Then, apply Heron’s formula to find the area of the triangle:
Area = √(s * (s – a) * (s – b) * (s – c))
Finally, double the area found and divide it by one of the sides acting as a base to get the corresponding height.
These four methods demonstrate various techniques to find the height of a triangle based on known information. Mastering these techniques will greatly help you solve an array of real-life scenarios and mathematical problems related to triangles.