Question

PLEASE HELP ITS URGENT!! Given: △ABC is isosceles; 1 ≅ 3 Prove: AB || CD

Answer 1

Answer:

AB ║ CD. (Proved)

Step-by-step explanation:

See the attached diagram of the triangle.

It is given that Δ ACD is an isosceles triangle.

Therefore, AC = AD and ∠ ACD = ∠ ADC, ⇒ ∠ 3 = ∠ 4 .......... (1)

Again, given that ∠ 1 = ∠ 3 ........... (2)

Now, from equations (1) and (2) we can write, ∠ 1 = ∠ 4

Now, AB and CD are two straight lines and AD is the transverse line and hence, ∠ 1 and ∠ 4 are alternate angles that are equal.

Therefore, AB and CD are parallel straight lines and AB ║ CD. (Proved)