Question

In a right angled triangle $ABC,\angle B={90}^{\circ }$ such that $AC=13cm,BC=5cm$. Then, find $AB$.

• A. $12cm$
• B. $17cm$
• C. $15cm$
• D. $14cm$

Answer 1

Answer: (A)

$12cm$

In a right angled triangle $ABC$, if $\angle B={90}^0$

using Pythagoras theorem, we have

${AC}^2={AB}^2+{BC}^2$

$AC=13cm,BC=5cm$

$\Rightarrow {13}^2={AB}^2+5^2$

$\Rightarrow 169={AB}^2+25$

$\Rightarrow 169-25={AB}^2$

$\Rightarrow AB=\sqrt{144}=12cm$