Question

Give reason for your reason

Answer 1

in this AB and DE are parallel lines so /_ DCA = /_ BCA( alternate angles of parallel lines)

so angle BCA = 50 degree

now sum of all angles of triangles are 180 degree

so

BCA+ ABC + ACB= 180

50 + 80 + ACB=180

ACB= 180-130

ACB=50

the triangle is isosceles since the two angles are equal.

MARK ME AS BRAINLIEST......

Answer 2

Step-by-step explanation:

Given: AB||CD...

Therefore, angle ABC = Angle ACB (alternate interior angles)

since, angle ABC = angle ACB,

AB = AC ( sides opp to equal angles are equal)

therefore ∆ABC is an isoscles triangle

HENCE PROVED!