Question

Find the surface area.

Answer 1

Surface area = lateral area + base area

Base area = r²π

Lateral area = πra (a is apotheme, 0,51 m)

0,51 m = cm 51 (0,51×100)

Find the radius. As you can see, the apotheme is the hypothenuse of the right triangle inside the cone. The heught of the cone is one leg. Apply Pitagora.

r = √51²-24² = √2601-576 = √2025 = 45 cm

Base area = 45²*pi = 2025pi cm²

Lateral area = 45*51*pi = 2295pi cm²

Surface area = 0,2025+0,2295 = 4320pi cm²