Question

help
me please for this math question

Answer 1

external radius = D/2
= 15/2 = 7.5 cm.
external area = πr^2
= 3.14× 7.5×7.5
=3.14 × 56.25
=176.625 cm^2
internal radius = D/2
= 13/2 =6.5cm
internal area = πr^2
=3.14×6.5×6.5
=3.14×42.25
=132.665cm^2
area of ring = external area - internal area.
= 176.625cm - 132.665cm
= 43.96cm^2