# C Program To Find Area Of Semi Circle | C Programs

C Program to find the Area of a Semicircle – In this particular article, we will detail in on the ways to find the area of a semicircle in C programming. The ways in which the area of a semicircle is calculated in this piece are as follows:

• Using Standard Method
• Using Function
• Using Pointers
• Using Macros

As we all know, a semicircle is exactly half that of a circle. A semicircle is cut right through the diameter of a circle. The diameter divides a circle into two semicircles.

The area of a circle can be calculated by multiplying half of its perimeter or circumference with that of its radius.

The area of a circle is

=> A = (1/2) πr^2 * r

=> A = πr^2.

Since a semicircle is equal to half of a circle, the area of a semicircle is also half of that of the area of a circle. Thus, the area of a semicircle is as follows:

A = (1/2) * πr^2

=> A = (1/2)πr^2.

Henceforth, this formula will be used in the upcoming Java programs to find the area of a semicircle. A semicircle is demonstrated in the image here: ## Using Standard Method

• For calculating the area of the semicircle, we need the radius of a circle.
• The value of radius will store into the variable “r”.
• By substituting the “r” value into the formula then we will get the area of the semicircle, that will be assigned to the variable “area”
Output:

### Using Function

• We are using the function float area(float r) to calculate the area of the semicircle, the return type of this function is a float.
• Using area(r)we are calling the function which is having float type argument.
• The called function area(float r) calculates the area of a semicircle and returns the value, the return value will be assigned to the variable “a”.
Output:

#### Using Pointers

• We are calling the function by passing addresses as arguments using area(&r, &a)
• Then called function area(float *r, float *a) which is having pointers as arguments will calculate the area of the semicircle, and that value will store into the variable “a”
Output:
##### Using Macros
• area(r) is a symbolic name to the expression (22*r*r)/(2*7).
• area(r) replaced with that expression given at #define.
Output: