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WAEC Mathematics 2023 Paper

Question : 18

Total: 50

\pi = \frac{22}{7})

Solution:

Concept:

Total surface area of a solid cylinder is the sum of the curved surface area and the areas of its two circular bases.

Explanation:

Given: radius

r = 8\,\mathrm{cm}

, height

h = 14\,\mathrm{cm}

, and

\pi = \frac{22}{7}

The formula for total surface area is:

TSA = 2\pi r h + 2\pi r^{2}

This can also be written as:

TSA = 2\pi r (h + r)

Substitute the given values into the formula:

TSA = 2 \times \frac{22}{7} \times 8 \times (14 + 8)

TSA = 2 \times \frac{22}{7} \times 8 \times 22

Now simplify the multiplication:

TSA = \frac{2 \times 22 \times 8 \times 22}{7}

TSA = \frac{7744}{7}

TSA = 1106.2857\ldots \,\mathrm{cm}^{2}

Correct to two decimal places:

TSA = 1106.29\,\mathrm{cm}^{2}

Answer:

1,106.29\,\mathrm{cm}^{2}

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