Question

Question no 4, 3rd sub question

a toy is a combination of cylinder, cone and hemisphere each with a radius 10cm as shown in the figure. Height of the conical part is 10 cm and total height is 60 cm. Find total surface area of the toy. ( pie =3.14, root 2 = 1.41)

Answer 1

height of conical part = 10 cm
height of hemisphere = radius of hemisphere = 10 cm
height of cylindrical part =60 cm - 10 cm - 10 cm
=40 cm
slant height of cone = 10 cm ×1.41 = 14.1cm
total surface area of toy =curved surface area of cylinder + curved surface of cone + curved surface area of hemisphere


total surface area of toy =2Πrh + Πrl +2 Πr ×r
= Πr (2h+l+2r)
= 3.14×40cm (2×10cm +14.1cm +2×10cm)
= 125.6cm (20cm +14.1cm +20cm)
=125.6cm (54. 1cm)
=6,794.96 square cm