### Home > CCA2 > Chapter 5 > Lesson 5.1.2 > Problem 5-30

5-30.

Write the equation of a circle with a center at *y*-axis (in other words, it touches the *y*-axis at only one point). Sketching a picture will help.

Since the circle is tangent to the *y*-axis, the length of the radius will be equal to the distance from the center to the *y*-axis.

Use the eTool below to graph the equation.

Click the link at right for the full version of the eTool: *CCA2 5-30 HW eTool*