12. The areas of two concentric circles are 1386 cm’ and 1886.5 cm’respectively. Find the width
of the ring.
Answers
Step-by-step explanation:
The areas of two concentric circles are 962.5 cm square and 1386cm 2 solution:
Given The Areas of two concentric circles are 1386 sq .cm and 1886.5 sq cm respectively.
Width of the ring = larger radius - smaller radius (of the concentric cricle)
W=R-r
Area of larger circle = π R π sq
1886.5 = 22/7(R sq)
1886.5×7/22=R sq
85.75×7=R sq
600.25= R sq
R=√600.25
R=24.5 cm
Area of smaller circle = π r sq
1386=22/7(r sq)
1386×7/22= r sq
63×7= r sq
r sq =441
r sq = √441
r= 21 cm Width of the ring (formed by concentric circles) = R - r
= 24.5-21
= 3cm
: width of the ring = 3cm