Very important question of mensuration including
very important concept of it.need solution!
Rd sharma class 10 maths exercise-15.4 mensuration.
we have to find the increase in area of the grassy
lawn in which the calf can graze given that a calf
is tied with a rope of length 6 m at the corner of
a square grassy lawn of side 20 m. If the length of
the rope is increased by 5.5 m.
Given,
The initial length of the rope = 6 m
Then the rope is said to be increased by 5.5m
So, the increased length of the rope = (6 + 5.5) = 11.5 m
We know that, the corner of the lawn is a quadrant of a circle.
Thus,
The required area = ¼ x π(11.5)2 – ¼ x π(5.5)2
= ¼ x 22/7 (11.52 – 62)
= ¼ x 22/7 (132.25 – 36)
= ¼ x 22/7 x 96.25
= 75.625 cm2