Question

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

Answer 1

47.1 cm

Explanation:

For this problem, I'll use an approximation of
`\pi \approx 3.14`, which is good enough for the level of accuracy we need. The definition of π itself is given by the equation

`\pi =(c)/(d)`

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

`c=\pi d\approx3.14d`

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

`c\approx3.14(15)=47.1`

So the circumference of this circle is approximately 47.1 cm.

Answer 2

Given,
Diameter of circle=15cm

so, radius= D/2= 15/2

we know that circumference=perimeter

2πr= 2×22/7×15/2=47.1428cm