### Home > A2C > Chapter 8 > Lesson 8.1.5 > Problem8-85

8-85.

Sketch a graph of $x^{2} + y^{2} = 100$.

1. Is it a function?

Does each x-value on the graph of the function have only one corresponding y-value?

2. What are its domain and range?

Domain: −10 ≤ x ≤ 10
Range: −10 ≤ y ≤ 10

3. Draw a central angle that measures $\frac { 2 \pi } { 3 }$ radians. If you remove this wedge of the circle, how much area remains?

See the unit circle graph at right.
What portion of the circle is shaded?

$\text{Since}\:\frac{2\pi}{3}\:\text{is} \ \frac{1}{3}\:\text{of the total angle in a circle, the remaining}$

$\text{area will be }\frac{2}{3}\:\text{of the total area.}$