Solve it quickly........
Answers
Question:
In the figure, arc SBT is one quarter of a circle with centre R and radius 6. If the length plus width of the rectangle ABCR is 8 then the perimeter of the shaded region is
(A) 8 + 3π
(B) 10 + 3π
(C) 14 + 3π
(D) 1 + 6π
(E) 12 + 6π
Solution:
Radius (r) = 6
SR = AC = RT = 6
AR = RC = 8
_____________ [ GIVEN ]
• We have to find the value of the shaded region.
______________________________
Now..
arc SBT = 2πr/4
=> 2π(6)/4
=> 3π
_____________________________
Area of the shaded region = side (SA + AC + CT) + arc SBT
We can write SA = (SR - AR) and CT = (RT - RC)
=> (SR - AR) + AC + (RT - RC) + arc SBT
=> SR - AR + AC + RT - RC + arc SBT
=> SR - (AR + RC) + AC + RT + arc SBT
Put the known values above
=> 6 - (8) + 6 + 6 + 3π
=> - 2 + 12 + 3π
=> 10 + 3π
_____________________________
Option (B) 10 + 3π
_________ [ ANSWER ]
______________________________