Question

In a right angled $△ABC$, right-angled at B, $\angle A+\angle C$ =

• A. ${90}^{\circ }$
• B. ${120}^{\circ }$
• C. ${180}^{\circ }$
• D. ${45}^{\circ }$

Answer 1

The correct option is A ${90}^{\circ }$

Consider the right angled $△ABC$, right-angled at B.


The angle sum property of a triangle states that the sum of the interior angles of any triangle is ${180}^{\circ }$.
So, $\angle A+\angle B+\angle C={180}^{\circ }$
$⟹\angle A+\angle C={180}^{\circ }-{90}^{\circ }$
$[\because \angle B={90}^{\circ }]$
$⟹\angle A+\angle C={90}^{\circ }$