Question

if the area of a semi circular field is 30800 sqm ,then find the perimeter of the field ?

Answer 1

Solutions :-

Given : Area of semicircular field = 30800 m

We know that,

Area of semicircle = (π r²)/2
=> 30800 = (π r²)/2
=> 30800×2 = (π r²)
=> 61600 = (22×r²)/7
=> 61600×7 = 22r²
=> 431200 = 22r²
=> 431200/22 = r²
=> 19600 = r²
=> r² = √19600 = 140

Diameter = Radius × 2 = 140 × 2 = 280 m

Find the perimeter of semicircular field :-

We know,
Perimeter of semicircle = 1/2 π × r + d unit
= 1/2 × 22/7 × 140 + 280 m
= 3080/7 + 280 m
= 440 + 280 m
= 720 m

Hence,
Perimeter of semicircular fields = 720 m

Answer 2

solution :-

in question

given :-

area of semicircular field = 30800sqkm

area of semicircle = 1/ 2 πr^2

using this formula we find radius of region.

area of semicircle = 30800sqm

1/ 2 πr^2 = 30800

${r}^{2} = 30800 \times 2 \times \frac{7}{22} = 19600$

r^2 = √19600

r = 140m

[ taking positive square root]

so,

the perimeter of the field = πr + 2r

$\frac{22}{7} \times 140 + 2 \times 140 = \\ \\ 440 + 280 \\ \\ = 720m$

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