Question

a conical depression is carried out of a hemisphere as shown in the figure.find the surface area of the solid obtained if radius of cone is 5cm​

Answer 1

The surface area of the solid = 4283.7 cm²

Step-by-step explanation:

Radius of Cone r1 = 5 cm

Radius of hemisphere r = 21 cm

Height of cone, h = 21 -5 = 19 cm

Slant height of cone, l =  $\sqrt{5^{2}+12^{2} }$

                                      = $\sqrt{25+144}$

                                      = $\sqrt{169}$

                                      = 13 cm

Surface area of solid = TSA of hemisphere + CSA of cone - Area of base of cone

    = 3πr² + πr1l - πr1²

    = 3 x $\frac{22}{7}$ x 21 x 21 + $\frac{22}{7}$ x 5 x 13 - $\frac{22}{7}$ x 5 x 5

    = $\frac{22}{7}$ x (1323 + 65 - 25)

    = $\frac{22}{7}$ x 1363

    = 4283.7 cm2