Question : A path of 4 m width runs round a semi-circular grassy plot whose circumference is 163 3/7 m. Find the area of the path in m2.
Doubt by Zoha
Solution :
Circumference of semi-circular grassy plot = 163 3/7
= 1144/7 m
2πr/2 = 11447/7
πr = 1144/7
22×r/7 = 1144/7
22×r/7 = 1144/7
22×r=1144
r = 1144/22
r = 52 m
Now, Radius of External circular boundary (R)
r = 1144/22
r = 52 m
Now, Radius of External circular boundary (R)
R = r+4 m (width)
= 52+4
= 56 m
= 56 m
Area of Grassy Path = π[R2-r2]/2
=22[(56)2-(52)2]/(7×2)
= 11[108×4]/7
= [11×432]/7
= 4752/7
= 678.857 m2
=22[(56)2-(52)2]/(7×2)
= 11[108×4]/7
= [11×432]/7
= 4752/7
= 678.857 m2
= 678.86 m2