Question discussion

A circle is inscribed in a square. Another circle concentric to this circle is drawn within the circle. The area of the ring formed by thes…

3618Medium DSSSB TGT Computer Science 0 replies

A circle is inscribed in a square. Another circle concentric to this circle is drawn within the circle. The area of the ring formed by these two circles is 1540 cm² and the difference between their radii is 7 cm. What is the perimeter (in cm) of the square? (Use π = ²²⁄₇)

A308
B352
C264
D336

Correct answer: A

Explanation

π(R² − r²) = 1540 gives (R − r)(R + r) = 490. With R − r = 7, R + r = 70, so R = 38.5 cm. Side of the square = 2R = 77 cm and the perimeter = 4 × 77 = 308 cm.

Join the discussion Report an error

Discussion 0

Nobody has replied yet. Start the discussion!