Grade 10 · Geometry & measurement

Circle theorems practice

Circle theorems is a grade 10 math skill aligned to Common Core standard HSG.C.A.2: identify and describe relationships among inscribed angles, radii, and chords. Below are 8 practice questions with answers and step-by-step explanations, drawn from the 15 circle theorems problems our math games drill.

CCSS HSG.C.A.215 questions in the bank
Sample questions

Try 8 for free

Question 1easy

A central angle measures 75°75°. What is the measure of its intercepted arc?

A central angle equals its intercepted arc, so the arc is 75°75°.

Question 2easy

An inscribed angle intercepts an arc of 140°140°. What is the inscribed angle?

Inscribed angle =1402=70°= \dfrac{140}{2} = 70°.

Question 3easy

An inscribed angle is 35°35°. What is the measure of its intercepted arc?

The intercepted arc is twice the inscribed angle: 2×35=70°2 \times 35 = 70°.

Question 4easy

An inscribed angle intercepts an arc of 50°50°. What is the inscribed angle?

Inscribed angle =502=25°= \dfrac{50}{2} = 25°.

Question 5easy

An inscribed angle intercepts an arc of 100°100°. What is the inscribed angle?

An inscribed angle is half its intercepted arc: 1002=50°\dfrac{100}{2} = 50°.

Question 6easy

An inscribed angle intercepts an arc of 60°60°. What is the inscribed angle?

An inscribed angle is half its intercepted arc: 602=30°\dfrac{60}{2} = 30°.

Question 7easy

An inscribed angle intercepts an arc of 120°120°. What is the inscribed angle?

An inscribed angle is half its intercepted arc: 1202=60°\dfrac{120}{2} = 60°.

Question 8easy

An inscribed angle is 45°45°. What is the measure of its intercepted arc?

The intercepted arc is twice the inscribed angle: 2×45=90°2 \times 45 = 90°.

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