The sum of the radii of two circles is 286 cm and the area between the concentric circles is 50336 cm2 . What are the radii (in cm) of the two circles? Take $π = \frac{22}{7}$.
Answer & explanation
Correct answer: option 2
We know that,
Area of circle = πr2
We have,
Sum of radii = 286cm
Area of concentric circles = 50336 cm2
Let area of bigger circle and smaller circle be R cm and r cm respectively.
= πR2 - πr2 = 50336
= R2 - r2 = 16016
= (R - r)(R + r) = 16016
= (R - r) = 56---- (1)
(R + r) = 286------(2)
From equation 1 and 2,
R = 171 cm and r = 115cm