Explanation

The circumference of a circle is given by the formula C = 2 * pi * r, where r is the radius of the circle, pi is a mathematical constant (approximately equal to 3.14) and C is the circumference.

In this case, the diameter of the circle is 7 cm. To find the radius, divide the diameter by 2: 7 cm / 2 = 3.5 cm

So, to find the circumference of a circle with a diameter of 7 cm, we can substitute this value for r in the formula: C = 2 * pi * 3.5 cm = 7 * pi approximately 22.0 cm

So the circumference of a circle whose diameter is 7 cm is approximately 22.0 cm.