This is the concept of algebra, we are required to calculate the area cut out of a cylinder represented by the function x^2+z^2=36;
The equation of a circle is given by:
(x-a)^2+(y-b)^2=r^2
where;
(a,b) are the center of the circle;
r=radius of the circle
re-writing our equation we have:
x^2+z^2=36
(x-0)^2+(z-0)^2=6^2
this implies that the center of the circle is (0,0) and the radius is 6 units;
Therefore the area will be given by:
Area=πr^2
Area=π*6^2
Area=36π=113.1 sq. units