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WAEC Mathematics 2016 Paper

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Question : 16

Total: 49

The volume of a pyramid with height 15cm is 90cm³. If its base is a rectangle with dimension xcm by 6cm, find the value of x

3
5
6
8

Solution:

Concept:

Volume of a pyramid is one-third of base area times height.

Explanation:

Given height is

15

cm and volume is

90

cm

^3

.

Base is a rectangle with dimensions

x

cm and

6

cm, so base area is

6x

cm

^2

.

Using the formula:

Volume

= \frac{1}{3} \times \text{base area} \times \text{height}

90 = \frac{1}{3} \times 6x \times 15

90 = \frac{1}{3} \times 90x

90 = 30x

x = \frac{90}{30}

x = 3

Answer:

x = 3

, so option A is correct.

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