Question

in triangle abc ab=ac and angle b =20 then find angle A

Answer 1

in a triangle,is 2 sides are eql , then it is isosceles triangle.
<c=<b= 20.
according to angle sum property , sum of angles in a triangle = 180.
a+b+c=180
a+2b=180
a=180-40
a=140
therefore <a=140 degrees