Question

Matt measures a subway token and calculates that it has an area of 254.34 square millimeters. What is the token's circumference? Use 3.14 for ?.

Answer 1

Answer:

The token's circumference is $56.52\ mm$

Step-by-step explanation:

step 1

Find the token's radius  

The area of the circle is equal to

$A=\pi r^{2}$

we have

$A=254.34\ mm^{2}$

so

$254.34=(3.14)r^{2}$

$r^{2}=254.34/(3.14)$

$r^{2}=81$

$r=9\ mm$

step 2

Find the token's circumference  

The circumference of the circle is equal to

$C=2\pi r$

we have

$r=9\ mm$

substitute

$C=2(3.14)(9)=56.52\ mm$