Question

Inner and outer radii of an annulus of a circle are 10cm and 4cm. Find the area of the annulus​

Answer 1

Step-by-step explanation:

2πr= perimeter formula.

using this, we get outer perimeter= 2×3.14×10= 62.8 approximate.

since 3.14 is approximate value.

then, inner perimeter = 2×3.14×4=25.12 approximate.

since 3.14 is an approximate value.

then we should subtract inner are from outer area, that is-

62.8 - 25.12 = 37.68 cm².

this is the area of the annulus

Answer 2

Answer:

264 cm²

Step-by-step explanation:

Inner radii(r) = 4 cm

Outer radii(R) = 10 cm

Area of the inner circle = πr² = 22/7*4*4 = 50.28 cm²

Area of the outer circle = πR² = 22/7*10*10 = 314.28 cm²

Area of the annulus = 314.28 - 50.28

                                 = 264 cm²