Question

What is the radius of thr brazilian coin that has a circumference of 84.78 mm? Explaim you work. Use 3.14 for pi

Answer 1

Hello there! Circumference is pi * diameter. Radius is ½ of the diameter. In order to find the diameter, all you have to do is divide the circumference by pi (3.14). 84.78/3.14 is 27. Now, divide that number by 2 to get 13.5. There. The radius of the Brazillian coin is 13.5 mm.

Answer 2

we know that

the circumference of a circle is equal to

`C=2\pi r`

where

r is the radius of the circle

in this problem we have

`C=84.78\ mm\\r=?\\\pi=3.14`

Solve for r

`C=2\pi r`

`r=(C)/(2\pi)`

substitute the values in the formula

`r=(84.78)/(2*3.14)`

`r=13.5\ mm`

therefore

the answer is

the radius of the brazilian coin is
`13.5\ mm`