Question

One angle of a right angled triangle is ${40}^{\circ }$ , then the measure of the other acute angle is

• A. ${45}^{\circ }$
• B. ${50}^{\circ }$
• C. ${65}^{\circ }$
• D. ${55}^{\circ }$

Answer 1

The correct option is B ${50}^{\circ }$

Let ABC be a right angled triangle.



Given ABC = ${90}^{\circ }$ and BCA = ${40}^{\circ }$

We need to find $\angle CAB$

From angle sum property

$\angle CAB+{40}^{\circ }+{90}^{\circ }={180}^{\circ }$

$\angle CAB+{130}^{\circ }={180}^{\circ }$

$\angle CAB={180}^{\circ }-{130}^{\circ }$

$\angle CAB={50}^{\circ }$

Hence measure of the other acute angle is ${50}^{\circ }$