Question

A semi-circle has a diameter of 32cm there is a another hole which is a semi-circle with a diameter of 16cm .Find the perimeter of the bigger semi-circle.(Take PI as 22/7)​

Answer 1

Perimeter of Circles

Perimeter of the object is 91.4285 cm

Step-by-step explanation:

The perimeter of a circle is defined as $2\pi r$

The perimeter of outer arc will be $2\pi r_{1} /2$

The perimeter of inner arc will be $2\pi r_{2} /2$

Where $r_{1\\}$ is radius of bigger semicircle and $r_{2}$ is radius of smaller semicircle

Given diameter of outer semicircle  = 32 cm

$r_{1\\}$ = 32/2 = 16 cm

Given diameter of outer semicircle  = 16 cm

$r_{2\\}$ = 16/2 = 8 cm

So the perimeter of the object = $\pi r_{1} +\pi r_{2} + 2 (r_{1} -r_{2} )$

Perimeter P = 22/7 * (16 +8 ) + 2 * 8 =

P = 22/7 * 24 +16

So P = 75.4285 +16 = 91.4285 cm