Test Index

JAMB Mathematics 2015 Paper

Question : 44

Total: 61

Solution:

Concept:

The curved surface area of a cone requires the slant height, found using Pythagoras' theorem with the radius and vertical height.

Explanation:

Given: radius

r = 3\,\mathrm{cm}

, height

h = 4\,\mathrm{cm}

and

\pi = 3.14

First, find the slant height

l

using

l^2 = h^2 + r^2

l^2 = 4^2 + 3^2 = 16 + 9 = 25

l = \sqrt{25} = 5\,\mathrm{cm}

The curved surface area of a cone is given by

\pi r l

So, area

= 3.14 \times 3 \times 5

Area

= 3.14 \times 15 = 47.1\,\mathrm{cm}^2

Answer:

47.1\,\mathrm{cm}^2

Go to Question:

Prev Question

Next Question