What you’ll learn
Radius, diameter, chord, secant, tangent.
Key idea
A diameter consists of two radii and is a special center-passing chord.
A diameter is a center-passing chord; chord endpoints alone do not guarantee center incidence.
Worked example
Enter the exact value or ordered values in the format requested below.
Circle O has radius 17 cm. Segment AB has endpoints on the circle and passes through O. Find AB in centimeters.
- AB passes through the center, so it is a diameter made of two radii of length 17.
- AB=17+17=34 cm.
Answer: 34
Quick Check
Evaluate a worked attempt at radius, diameter, chord, secant, tangent, identify the first invalid step, and provide the correction.
Circle center O=(0,0) has radius 4. Points A=(-16/5,12/5), B=(16/5,12/5) are on it. Student Step 1 calls AB a chord. Step 2 calls it a diameter and assigns length 8. Locate the first invalid step and correct the classification and length.