NECO 2023 · Paper 1 · Q31

Expressions, formulae & change of subject

Given that $T = 2\pi\sqrt{\dfrac{l}{g}}$ , find the value of $T$ when $\pi = \frac{22}{7}$ , $l = 16$ and $g = 10$ .

Worked solution (try it first)

Inside the root: $\frac lg = \frac{16}{10} = 1.6$ , and $\sqrt{1.6} = 1.2649$ .
Multiply by $2\pi$ : $2 \times \frac{22}{7} = \frac{44}{7}$
$= 6.2857$ .
So $T = 6.2857 \times 1.2649 = 7.95$ , option D.

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