In , BC = AB and = 80^ . Then is equal to: - Vidyadip

Question

In $\triangle\text{ABC},$ BC = AB and $\angle\text{B} = 80^\circ.$ Then $\angle\text{A}$ is equal to:

✓

Answer

50º
Solution:
Given: $\triangle\text{ABC},\ \text{(BC=AB)}$ and $\angle\text{B} = 80^\circ$

As BC = AB
So it is an isosceles triangle.
let $\angle\text{C} = \angle\text{A} = \text{x}$
∠B = $\angle\text{B} = 80^\circ$ (given)
As we know $\angle\text{A} + \angle\text{B} + \angle\text{C} = 180^\circ$
⇒ x + 80º + x = 180º
⇒ 2x = 180º - 80º
⇒ 2x = 100º
⇒ x = 50º
So, $\angle\text{C} = \angle\text{A} = 50^\circ$

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