The diameter of a round dinner plate is 10 inches. what is the area of the plate

So we wan't to know what is the area of a round dinner plate with a diameter of 10 inches. The formula for area of a circle is A=pi*r^2 and the diameter D=2r, so in our case: r=D/2. When we input that into the area we get: A=3.14 * (D/2) ^2 and that is: A=78.5 in^2.