We are given the image of a circle with a straight line passing through the center of the circle and touching its edges. Such a line is known as the diameter of the circle. From the image we can see the length of the diameter of the circle is d =15 units.
Radius is define as half of the diameter. Since the diameter is 15 units, the radius of the given circle will be half of 15 which is r = 7.5 units.
Circumference of the circle = C = 2πr
Using the value of radius(r), we can write the circumference as: