Question

first, find m∠jqk.
m∠jqk = 70 °
now, find m∠mqn.
m∠mqn = 180 °
vertical angles have the same measure.

Explanation:

Step1: Calculate sum of known angles

Sum = 70° + 30° + 80° = 180°

Step2: Find m∠MQN

Total around Q = 360°, so m∠MQN = 360° - 180° = 180°

Answer:

180