Question

In the figure, in ∆ABC, AB = AC. ∟A = 80° .Find the value of x.
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Answer 1

Question:

In the figure, in ∆ABC, AB = AC. <A = 80° . Find the value of x.

Given:

side AB = side AC

<A=80°

Answer:

In ∆ABC

AB=AC (1)

<A=80° (2)

Therefore, ∆ABC is isosceles triangle....(from 1 & 2)

angle B = angle C = x (isosceles triangle thm)

A+B+C=180°(sum of angles of ∆ is 180°)

80°+ x + x = 180

2x=180-80

2x=100

x=100/2

x=50°

therefore, angle B = angle C = 50°