Answer:
Step 1: It should be m∠m + m∠n + m∠o = 180° (sum of angles in a triangle)
Step-by-step explanation:
He made the mistake in Step 1: m∠m + m∠n + m∠p = 180°
It should be m∠m + m∠n + m∠o = 180°
Then only, he can equate it with m∠o + m∠p in step 3.
So, m∠p is the exterior angle and m∠m and m∠n are the two remote interior angles.
m∠o is the adjacent angle to m∠p. They form a linear pair.
Hence, the correct answer is Step 1.
