Question

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In ∆ABC,AB=AC and angleB=2/5th of Angle A. Find the measure of Angle A

Answer 1

let ABC is a triangle
ab is equal to AC given
Angle B is the two fifth of angle A
let , angle A = x
then angle b = 2/5x
AB=AC
then angle B is equal to angle C
then angle C 2/5x
$x +\frac{2x}{5} + \frac{2x}{5} = 180$
$\frac{9x}{5} = 180$
$x = 100$

angle A =100°