Question

4. In A ABC, Angle B = 90° and AB = BC, then find
Angle A.​

Answer 1

Angle A = 45 degrees


{ since AB=BC , it is an isosceles triangle , and we know that angles opposite to equal sides of an isosceles triangle are equal , hence angle A = angle C,

by angle sum , A+B+C = 180
A=C
so 2A = 180-B
4 = 180-90/2 = 90/2 = 45 degrees

Answer 2

According to angle sum property

Angle A + Angle B + Angle C = 180

A+B+90=180

A+B=180-90

A+B=90

In triangle if opposite sides are equal then opposite angles are also equal

So AB=BC

Then Angle A = Angle B

So Angle A = 45°

Angle B = 45°

HOPE THIS MAY HELP YOU