## Semicircle

In this page semicircle we are going to see how to find area and perimeter (circumference) of a semi-circle. To understand this topic much better we have given different kinds of example problems.

Semicircle is exactly half the entire circle.

Area of Semi-circle  = (1/2) Π r²

Here r represents the radius of the circle. Now let us see example problems based on the above formula.

Example 1:

Find the area of the semi-circle whose radius is 7 cm.

Solution:

Area of Semi-circle  = (1/2) Π r²

Here r= 7 cm and Π = 22/7

= (1/2) x (22/7) x 7²

= (1/2) x (22/7) x 7 x 7

= 1 x 11 x 7

= 77 cm²

Example 2:

Find the area of the semi-circle whose radius is 3.5 cm.

Solution:

Area of Semi-circle  = (1/2) Π r²

Here r = 3.5 cm and Π = 22/7

= (1/2) x (22/7) x (3.5)²

= (1/2) x (22/7) x 3.5 x 3.5

= 1 x 11 x 0.5 x 3.5

= 19.25 cm²

Now let us see formula to find the perimeter (circumference) of a semi-circle.

Perimeter of semi circle = (Π+2)r

Example 1 :

Find the circumference of the semi-circle whose diameter is 7 cm.

r = diameter/2

r = 7/2

r = 3.5

Now we can apply the formula

Circumference of semi-circle = (Π + 2)r

here r = 3.5 and Π = 22/7

= [(22/7)  + 2]x 3.5

= (22+14) x 0.5

= 36 x 0.5

= 18 cm

Example 2 :

Find the circumference of the semi-circle whose diameter is 42 cm.

r = diameter/2

r = 42/2

r = 21

Now we can apply the formula

Circumference of semi-circle = Πr

here r = 21 and Π = 22/7

= (22/7) x 21

= 22 x 3

= 66 cm

Example 3 :

Find the circumference of the semi-circle whose diameter is 56 cm.

r = diameter/2

r = 56/2

r = 28

Now we can apply the formula

Circumference of semi-circle = Πr

here r = 28 and Π = 22/7

= (22/7) x 28

= 22 x 4

= 88 cm

Related Topics

Semicircle to Home