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 area of the quadrant OACB and shaded region.Given that
OACB is a quadrant of a circle with center O and radius 3.5 cm. If OD = 2 cm.
Given,
Radius of small quadrant, r = 2 cm
Radius of big quadrant, R = 3.5 cm
(i) Area of quadrant OACB = ¼ πR2
= ¼ (22/7)(3.5)2
= 269.5/28 = 9.625 cm2
(ii) Area of shaded region = Area of big quadrant – Area of small quadrant
= ¼ π(R2 – r2)
= ¼ (22/7)(3.52 – 22)
= ¼ (22/7)(12.25 – 4)
= ¼ (22/7)(8.25)
= 6.482 cm2