Chapter 2, Problem 11CT

To determine

Toprove: $\angle 6\cong \angle 8$

Explanation of Solution

Given information: $\angle 6\cong \angle 7$ and $\angle 7\cong \angle 8$

Formula used: According to transitive property of congruence, two things (sides or angle) that are equal to the same thing (sides or angle) are congruent to each other. That is if $a\cong b,b\cong c$ then $a\cong c$

Proof:

  $\angle 6\cong \angle 7$ (i)

  $\angle 7\cong \angle 8$ (ii)

According to the transitive property of congruence, two things that are equal to the same thing (sides or angle) are congruent to each other.

From equation (i) and (ii), $\angle 6,\angle 8$ are congruent to the angle $\angle 7$

So,

  $\angle 6\cong \angle 8$