A. To find the area of a circle you need to use the formula A= π r²
The radius (R) is half of the diameter . . . that's 6.5 cm .
r² = ( 6.5)² = 42.25 cm²
Area = π r² = 42.25 π = 132.7 cm²
B. Area of a rectangle is just (length) x (width).
Length = 12 cm
Width = 5 cm
Area = (12 cm) x (5 cm) = 60 cm²
C. The shaded portion is the part of the circle that's NOT in the rectangle. So its area is (area of the circle) - (area of the rectangle)
Area = (132.7 cm²) - (60 cm²) = 72.7 cm²