Question

A semicircular sheet of paper of diameter 28 cm is bent to form an open conical cup , find the capacity of cup

Answer 1

r of semicircle = 14cm
circumference of semicircle = base circumference of cone
2πr*½ = 22/7 * 14 = 44 cm
so base circumference of cone = 44 cm
2πr = 44
πr = 22
22/7 * r = 22
r = 7 cm
so radius of the cone is 7 cm
slant height of cone = r of semicircle
so l = 14 cm
l² = r² + h²
14² = 7² + h²
h² = 196 - 49 = 147
h = 12.12 cm
volume of cone = ⅓πr²h
= 1/3 * 22/7 * 7² * 12.12
= 13065.36/21
= 622.16 cm³