Question

a path 2 m wide surrounds a circular pond of diameter 40 m . How many cubic meter of grave are required to grave the path to a depth of 7 cm

Answer 1

Given
Dia of pond =40m
Width of path=2m
(check diagram in image)

Area of path = area of outer circle - area of inner circle

=pi R²- pi r²

=pi(R²-r²)

R=20+2=22
r=20

=pi (484-400)

=22/7 x 84

=264m²

Grave requires=area of path x depth

Depth=7cm =0.07m

=260x0. 07

=18.48m³

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