Question

In $△ABC,\angle B$ is right angle. If $a=16$ and $c=12$ then $b=$ _____.

• A. $8$
• B. $18$
• C. $20$
• D. $28$

Answer 1

The correct option is C $20$

By applying Pythagoras theorem,
In $△ABC$,
$A{C}^2=A{B}^2+B{C}^2$
$\therefore b^2=c^2+a^2$
$\therefore b^2=(12{)}^2+(16{)}^2$
$\therefore b^2=144+256$
$\therefore b^2=400$
$\therefore b^2=\pm \sqrt{400}$
$\therefore b^2=\pm 20$
Since length cannot be negative, hence, $b=20$.