waecmaths question:
A straight line passes through the points P(1, 2) and Q(5, 8), Calculate the length PQ
Option A:
$4\sqrt{11}$
Option B:
$4\sqrt{10}$
Option C:
$2\sqrt{17}$
Option D:
$2\sqrt{13}$
waecmaths solution:
$\begin{align} & P({{x}_{1}},{{y}_{1}})=(1,2) \\ & Q({{x}_{2}},{{y}_{2}})=(5,8) \\ & d=\sqrt{{{({{x}_{2}}-{{x}_{1}})}^{2}}+{{({{y}_{2}}-{{y}_{1}})}^{2}}} \\ & d=\sqrt{{{(5-1)}^{2}}+{{(8-2)}^{2}}} \\ & d=\sqrt{{{4}^{2}}+{{6}^{2}}} \\ & d=\sqrt{16+36}=\sqrt{52}=\sqrt{13\times 4}=2\sqrt{13} \\\end{align}$
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