Question

A toy is in the form of a cone mounted on a hemisphere. The diameter of the base and the height of the cone are 6 cm and 4 cm respectively. Determine the surface area of the toy​

Answer 1

Solution :-

Diameter of the base of the cone (d) = 6cm

Radius = d/2 = 6/2 = 6 cm

Height of the cone (h) = 4 cm

l = √r² + h²

⟹ √3² + 5²

⟹ √9 + 16

⟹ √25

⟹ 5 cm

C.S.A of the cone = πrl

⟹ 22/7 × 3 × 5

⟹ 330/7 cm²

C.S.A. of hemisphere = 2πr²

⟹ 2 × 22/7 × 3 × 3

⟹ 396/7

Surface area of the toy = C.S.A of cone + C.S.A of hemisphere

⟹ 330/7 + 396/7

⟹ 726/7

⟹ 103.71 cm²

Answer 2

Answer:

160.2 cm²

Step-by-step explanation:

note they said surface area which means total surface area(tsa)

and not curved surface area(csa)

tsa of cone is pi×r(r+l)

               d=6,r=3

        r²+h²=l²    h=4 ,r=3

        l²=25  

     l=5

     pi×3(3+5)

    75.4

tsa of an hemisphere=3×pi×r²=84.8

toy     tsa=75.4+84.8=160.2