Difficulty: Easy
Correct Answer: 25
Explanation:
Introduction / Context:
Inscribed angles that subtend the same arc as a given central angle measure exactly half the central angle. This is a fundamental property of circles.
Given Data / Assumptions:
Concept / Approach:
Inscribed angle theorem: inscribed angle = (1/2) × corresponding central angle for the same arc.
Step-by-Step Solution:
Verification / Alternative check:
All inscribed angles standing on arc QR are equal; each is half of the 50° central angle.
Why Other Options Are Wrong:
20°, 30°, 15°, 35° are not half of 50°.
Common Pitfalls:
Confusing inscribed angle with central angle or doubling instead of halving.
Final Answer:
25
Discussion & Comments