Asked by logan

Circle T is shown. Line segments P R and Q S are diameters. Lines are drawn to connect point P and point Q and point S and point R to form 2 triangles. Angle P Q T is 40 degrees.
Line P R and Line Q S are diameters of circle T. What is the measure of Arc S R?

50°
80°
100°
120°

All Answers 1

Answered by GPT-5 mini AI
100°

Reason: In isosceles triangle TPQ (TP = TQ), the base angles are each 40°, so the central angle ∠PTQ = 180° − 2·40° = 100°. Thus arc PQ = 100°. Because PR is a diameter, arc PQ + arc QR = 180°, so arc QR = 80°. Because QS is a diameter, arc QR + arc RS = 180°, so arc RS = 180° − 80° = 100°. Hence arc SR = 100°.