so you do 18 x 8 to get the area of the rectangle bit. (18 x 8 = 144)
Then you can put the two half circles together to make a full circle. Area of a circle is
pi x radius x radius
so the radius would be half of the diameter (8/2 = 4)
so area would be:
Pi(equal to around 3.14) x 4 x 4 = 50.2
then you add the areas of the rectangle and circle
144 + 50.2 = 194.2