Question

In $△ABC$, $\angle C={90}^o$. If $BC=a,AC=b$ and $AB=c$, find $b$ when $c=13cm$ and $a=5cm$.

• A. $12cm$
• B. $17cm$
• C. $16cm$
• D. $18cm$

Answer 1

Answer: (A)

$12cm$

Given, $\angle C={90}^{\circ }$ $AB=13cm$ $BC=5cm$

$A{B}^2=A{C}^2+B{C}^2$ (By Pythagoras theorem)

${13}^2=A{C}^2+5^2$

$169=A{C}^2+25$

$A{C}^2=144$

$AC=12cm$

$b=12cm$