First you need to find the area of the whole circle.
The radius is given as 10, so just insert 10 into the equation of the area of a circle equation.
Putting
after the 100 because that is what is commonly done.
Because the circle is then being split into 4 equal sections, we need to find 1/4 of the area of the whole circle to find the area of one of these sections.
Since the area of the whole circle is
then we just divide that by 4,
leaving us with 25
and that is our final answer