The formula for the area (#color(red)(A_circ)#) of a circle with radius #color(blue)r# is #color(white)("XXX")color(red)(A_circ)=picolor(blue)r^2#
where #pi# is a standard constant approximately equal to #3.14159#
Substituting #color(blue)5# for #color(blue)r# in the formula gives the Answer above.