How To Find The Perimeter Of A Semi Circle
The continuous closed line that makes the boundary of a two-dimensional shape is known as the perimeter. It's easy to work out the perimeter of a shape with straight edges, such as a square, because you simply add the lengths of each edge together. A different formula is required to work out the perimeter of a semi circle (a circle cut in half), because it consists of a curved edge as well as a straight edge. That formula is
\(P = \frac{1}{2} πd + d\)
where d is the diameter of the semi circle.
1. Remember Pi Constant
Apply the number pi (π) to the formula
\(P = \frac{1}{2} πd + d\)
Pi is a circle's circumference divided by its diameter and is always the same value, 3.14.
2. Note the Diameter
To find the perimeter of a semi circle, you have to know the diameter (the length of its straight edge). For example, if the diameter of your semi circle is 12 centimeters, the formula becomes
\(P = \frac{1}{2} ×(3.14×12) + 12\)
3. Break Down the Equation
Work out
\(3.14 × 12 = 37.68\)
Then work out
\(37.68 ÷ 2 = 18.84\)
You now have the perimeter of the curved edge of the semi circle. But a semi circle also has a straight edge, which is why you have to add the length of the diameter to calculate the whole perimeter. In this case, work out
\(18.84 + 12 = 30.84\)
The perimeter of your semi circle is 30.84 centimeters.
Cite This Article
MLA
Gillespie, Claire. "How To Find The Perimeter Of A Semi Circle" sciencing.com, https://www.sciencing.com/perimeter-semi-circle-4489560/. 16 November 2020.
APA
Gillespie, Claire. (2020, November 16). How To Find The Perimeter Of A Semi Circle. sciencing.com. Retrieved from https://www.sciencing.com/perimeter-semi-circle-4489560/
Chicago
Gillespie, Claire. How To Find The Perimeter Of A Semi Circle last modified March 24, 2022. https://www.sciencing.com/perimeter-semi-circle-4489560/