Abookmark is shaped like a rectangle with a semicircle attached at both ends. the rectangle is 12 cm long and 4 cm wide. the diameter of each semicircle is the width of the rectangle. what is the area of bookmark ? use 3.14 for pie

So you know that the are of a rectangle is Length x width, so that part is simply 12x4, which =48 sq cm. 
To find the area of the two ends of the bookmark, two semicircles make one circle, so you can just find the area of one circle. The formula for the area of a circle is (3.14) x r². Because the diameter of the circle is the same as the width of the rectangle, half of the 4cm is the radius (2cm). 
Area of Circle= (3.14)x(2²)=12.56 cm sq.
Total area = Area of rectangle + Area of Circle
TA= 48 + 12.56
TA= 60.56 sq cm