Answer:

Explanation:
The formula to calculate the lateral area of a cylinder is: 

where h is the height of the cylinder, and c is the circumference (perimeter) of the circular base:
 
 where r is the radius
 where r is the radius
To calculate the circumference we need the radius of the circle, which we can calculate because we know that the area the circle is: 
 ,
,
substituting this in the formula for the area of a circle:
 
 

and solving for the radius: 

now that we know the radius, we calculate the circumference:
 
 
and finally we go back to the formula for the lateral area:

and substitute the height: 
 and the circumference:
 and the circumference:
