Question

If perimeter of a semicircle is 72 cm then its radius is

Answer 1

perimeter of semi circle is 2r + ¥r (take ¥ as pi is not in keyboard )

r(2+¥)=72

r=72÷36 ×7

r =72×7×1/36

r =2× 7

=14

Answer 2

The radius is 14 cm.

Step-by-step explanation:

Given : If perimeter of a semicircle is 72 cm.

To find : Its radius ?

Solution :

The perimeter of the semicircle is  $P=\frac{1}{2}\pi \times d+d$

Perimeter of a semicircle is 72 cm.

$72=d(\frac{1}{2}\pi+1)$

$72=d(\frac{1}{2}\times \frac{22}{7}+1)$

$72=d(\frac{22+14}{14})$

$72=d(\frac{36}{14})$

$d=\frac{72\times 14}{36}$

$d=28$

The diameter is 28 cm.

The radius is $r=\frac{d}{2}$

$r=\frac{28}{2}=14$

Therefore, the radius is 14 cm.

#Learn more

If the surface area of a sphere is 5544 cm2 find the volume

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