Question

Find the surface area of the figure below​

Answer 1

310.8m²

Explanation:

GIVEN :-

• Diameter = 9m ⇒ Radius (r) = 9/2 = 4.5m
• Slant height (l) = 13m

TO FIND :-

• Surface area of the whole figure.

FORMULAES TO KNOW BEFORE SOLVING :-

• Curved surface area of cone =
  `\pi rl` (where r = radius & l = slant height)
• Curved surface area of hemisphere =
  `2\pi r^2` (where r = radius)

PROCEDURE :-

In the figure , the cone is mounted on a hemisphere.

⇒ Radius of cone = Radius of hemisphere = 4.5m

Total surface area of the figure = Curved surface area of both cone & hemisphere.

⇒

• Curved surface area of cone =
  `\pi rl = 3.14 * 4.5 * 13 = 183.69m^2` ≈ 183.7m²

• Curved surface area of hemisphere =
  `2\pi r^2 = 2 * 3.14 * (4.5)^2 = 127.17m^2` ≈ 127.1m²

∴ Total surface area = 183.7 + 127.1 = 310.8m²