Question

3. If the area of a semi-circular field is
30800 sq m, then find the perimeter of the field.​

Answer 1

Answer:

Area = 1/2πr 2 =30800

r2=30800x2x7/22=19600

r =v19600 = 140

perimeter=πr+2 r

22/7x140+2x140

440+280=720m

Answer 2

Answer:

440 m

Step-by-step explanation:

Area of semi circle = 1/2×pi×r^2

According to question:

1/2×pi×r^2=20800 m^2

r^2 = 30800 ×7 ×2 /22 = 1400 × 14

r^2 = 19600 m^2

r = square root of 19600

r = 140 m

Perimeter=1 /2×2×pi×r = pi× r

= 22/7×140

=22×20

=440 m