Question

Q.4. If area of semicircular region is 1232 sq cm , find its perimeter.

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Answer 1

Area of the semicircular region=1232cm²

Area of a semicircle----

$= > \frac{\pi {r}^{2} }{2}$

=>22/7×r²/2=1232

=>22/7r²=1232×2

=>22/7r²=2464

=>r²=(2464×7)/22

=>r²=784

=>r=28 cm

Perimeter of a semicircle----

$= > \pi \ \times r$

=>22/7×28

=>88cm

Answer 2

Answer:

Perimeter of semi circular = πr+2r

Where r is radius , π = 22/7

πr+2r= 144 (given)

(22/7)r +2r = 144

22r+14r = 144*7 (multiply both sides by 7)

36r = 144*7

r= 144*7/36 = 28

radius =28 cm

Area =( 1/2)πr^2

Area=( 1/2 )*(22/7)*28*28

= 1232cm^2

Ans : area is 1232 cm^2