Calculate the circumference of the following circles correct to one decimal place

47.1 cm

Step-by-step explanation:

For this problem, I'll use an approximation of , which is good enough for the level of accuracy we need. The definition of π itself is given by the equation

where c is the circumference of a circle and d is its diameter. If we want to find the circumference, we can simply multiply both sides of that equation by d to get the formula

Here, we're given d = 15 cm, so plugging that in, we find our circumference to be

So the circumference of this circle is approximately 47.1 cm.