Exercise 2 Page 701

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 $\overline{EF}$ is a segment that intersects the circle and its two endpoints, $E$ and $F,$ are on the circumference. Therefore, it is a chord.

Diameter

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

Radius

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