Question

Construct an isosceles $△ABC,$ where base $AB=7cm$ and $\angle ABC={50}^o$. Also, find the measure of $\angle ACB$.

• A. ${50}^0$
• B. ${80}^o$
• C. ${100}^o$
• D. ${120}^o$

Answer 1

The correct option is B ${80}^o$

$AB=7$ cm $,\angle ABC={50}^{\circ }$

As the triangle is isosceles therefore $\angle CAB={50}^{\circ }$

Steps of construction:

1. Draw a line segment $AB=7$ cm.

2. At $A$ draw an angle of ${50}^{\circ }$ and extend the arm.

3. At $B$ draw an angle of ${50}^{\circ }$ and extend the ray such that it intersect the previous ray at $C$

4. Join $A$ to $C$ and $B$ to $C$

Now measure $\angle ACB$

$\angle ACB={80}^{\circ }$