Question

Find the radius and perimeter of a semi circle whose area is 77 cmsquare

Answer 1

Answer:

Radius = 7.001 cm

Perimeter = 43.988 cm

Step-by-step explanation:

Area of semi-circle = 77 cm square

Area of semi-circle = $\frac{1}{2}*\pi *r^{2}$

So,

$[tex]\frac{1}{2}*\pi *r^{2}=77\\\\r^{2} = \frac{154}{\pi}=49.01972\\\\r=\sqrt{49.01972}=7.001 cm$[/tex]

We know, perimeter or circumference = 2πr

So,

Perimeter = 2*π*7.001 = 43.98 cm

Answer 2

Answer:

Area of semi circle = (π*r*r)/2

77=(22/7*r*r)/2

r=+7,-7

since, radius is positive it +7 cm

and calculate perimeter with formula

πr+d , d is diameter