Question

Triangle $ABC$ is right -angled at $C$. Find $BC$, If $AB=9cm$ and $AC=1cm$.
In each case, answer correct to two place of decimal.

• A. $6\sqrt{7}cm$
• B. $6\sqrt{5}cm$
• C. $4\sqrt{5}cm$
• D. $4\sqrt{3}cm$

Answer 1

The correct option is C $4\sqrt{5}cm$

$\Delta ABC$ is right angled at $C$.

$AB=9cm$

$AC=1cm$

Applying pythagoras theorem,

$A{B}^2=B{C}^2+A{C}^2$

$\Rightarrow 9^2=B{C}^2+1^2$

$\Rightarrow B{C}^2=80$

$\Rightarrow BC=\sqrt{80}=4\sqrt{5}cm$