HAVE NAMED THE RECTANGLE AS ABCD

A IS THE VERTEX AT LEFT HAND CORNER, B AT RIGHT HAND CORNER, C AND D ARE THE VERTICES ON THE DIAMETER OF THE SEMI-CIRCLE

Let the center of the circle be at O

Radius of circle=OA

NOW OA=SQRT(100+64)=SQRT(164)=RADIUS

AREA OF SEMICIRCLE-1/2(PI*OA*OA)=82PI

SHADED AREA=AREA OF SEMICIRCLE-AREA OF RECTANGLE

=82*PI-160