Exercise 2 Page 719

Recall the definitions of radius, chord, and diameter.

Example Chord: EF
Example Diameter: DF
Example Radius: DN

Practice makes perfect

Before identifying teach feature of the graph, let's review some important definitions about circles.

Radius: A segment whose endpoints are the center and any point on the circumference of a circle.
Chord: A segment whose endpoints are on the circumference of a circle.
Diameter: A chord that contains the center of the circle.Now, consider the given diagram.

Chord

We can see that EF is a segment that intersects the circle and its two endpoints, E and F, are on the circumference. Therefore, it is a chord.

Diameter

DF is a chord, since it intersects the circle and its two endpoints, D and F, are on the circumference. But DF also crosses the center N. Therefore, it is a diameter.

Radius

According to the definitions, DN is a radius, since its a segment whose endpoints are the center and a point on the circumference.

Exercises p.719-723

Hints