In this video, we will write a C program to find the area and perimeter of a semicircle. Semicircle is a one-dimensional locus of points that forms half of a circle. The area of a semicircle is half the area of the circle from which it is made. Any diameter of a circle cuts it into two equal semicircles. 

Formula: 
Area of Semi-Circle = 1⁄2 * π *r2 
The perimeter of Semi-Circle = π *r 
where “r” is the radius of the semicircle. 

Examples: 

Semicircle Area and Perimeter: 
A = πr²/2 = 12.5 * π [cm²] 
≈ 39.27 [cm²] 

Perimeter (L) = πr + d = 5 * π + 10 [cm] 
≈ 25.708 [cm] 

Calculate Area & Perimeter of Semicircle - 2 Approaches
 

1) Using formula: 
Step 1: Take input R from the user. 
Step 2: Calculate the area and perimeter using a simple formula of the semicircle. 
Step 3: Print the result. 

2) Using function: 
Step 1: Create user define function. 
Step 2: Calculate area and perimeter using function. 
Step 3: Print the result. 

The Time and Space complexity of both the approaches are O(1).