Question

The longest straight line that can be drawn to connect two point on the circumference of a circle whose radius is 9 inches is

Answer 1

18 inches. The longest line would be the diameter. Since the radius is half of the diameter, 9x2=18

Answer 2

18 inches.

Explanation:

We can connect two points of a circle in many ways, as you can see in the picture below.

The longest straight line that you can draw to connect two points is the diameter, that is, the straight line that passes through the center of the circle.

If the circle has 9 inches of radius the diameter will be 9+9 = 18 inches.