Circle Parts and Angle Measures

Understand circle parts and angle measures.

Lesson 1 of 53 parts Practice Flashcards

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Radius and Diameter

Objective: Apply radius and diameter.

A radius joins a center to a point on the circle; diameter=2r.

Worked examples

Try itA circle has radius 4. Find its diameter.Show answer

8. Diameter is twice the radius.

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Objective: Apply radius and diameter.

A radius joins a center to a point on the circle; diameter=2r.

Worked examples

Try itA circle has radius 4. Find its diameter.Show answer

8. Diameter is twice the radius.

Objective: Apply central angles.

A central angle has its vertex at the center and equals the measure of its intercepted minor arc.

Worked examples

Try itA central angle measures 25°. What is its intercepted minor arc measure?Show answer

25°. A central angle matches its intercepted minor arc measure.

Objective: Apply circle equations basics.

A circle centered at (h,k) with radius r satisfies (x−h)²+(y−k)²=r².

Worked examples

Try itCircle center (1,3) and radius 4: which is its equation?Show answer

(x−1)²+(y−3)²=16. Use (x−h)²+(y−k)²=r².

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