Here, ∠PRQ and ∠PRT are angles in a linear pair.

m∠PRQ + m∠PRT = 180°

∴ 70 + m∠PRT = 180

∴ m∠PRT = 180 – 70

∴ m∠PRT = 110°

Now, ∠PRT is the exterior angle of ∆PQR.

∴ m∠P + m∠Q = m∠PRT

∴ m∠P + m∠P = m∠PRT

….(The measures of ∠P and ∠Q is same)

∴ 2m∠P = 110

∴ m∠P = 110/2

∴ m∠P = 55°

∴ m∠Q =