The smallest video camera in the world is 0.99 mm and the diameter is the diameter of the video camera less than or greater than 0.1 millimeters?

Hurry and answer this! circle x with a radius of 6 units and circle y with a radius of 2 units are shown which steps would prove the circles similar? translate the circles so they share a common center point, and dilate circle y by a scale factor of 4. translate the circles so the center of one circle rests on the edge of the other circle, and dilate circle y by a scale factor of 4. translate the circles so they share a common center point, and dilate circle y by a scale factor of 3. translate the circles so the center of one circle rests on the edge of the other circle, and dilate circle y by a scale factor of 3

We just started the introduction into circles and i have no idea how to do this.

What is the product? a-3/15a × 5/a-3