Question

Find the area of a circular ring whose external and internal diameters are 10 cm and 4 cm respectively.​

Answer 1

Answer:

84π cm (or) 263.76 cm

Step-by-step explanation:

given,

R = 10 cm

r = 4 cm

Area of outer circle, A1 = πR^2 = 100π

Area of inner circle, A2 = πr^2 = 16π

Area of ring = A1 - A2 = (100-16)π = 84π = 263.76 cm

Answer 2

Answer:

The area of the circular ring is

π(r2^2 -r1^2)

here r1 =internal diameter and r2 =external diameter

so the answer is =π(10^2-4^2)

=263•8