Question

a play-top is in the form of a hemisphere surmounted on a cone the diameter of the hemisphere is 3.6cm.the total height of the play top is 4.2 cm.find it's total surface area.​

Answer 1

given

diameter of =3.6 cm

total height = 4.2 cm

to find

t.s.a

solution

1. t.s.a =c.s.a of hemisphere +c.s.a of cone

c.s.a of hemisphere=2π r*r

radius =36/20 =2*22/7*36/20*36/20=20.36sq.cm

c.s.a of cone =πrl

l=8.17

=22/7*36/20*8.17=46.21sq.cm

substituting the values in 1.

20.36+46.21=66.57sq.cm (approx)

ans.=66.57sq.cm