If f(x + 1) = 2x2 – 3, then flx)= And f(a) = 4, then a =

Well , the diameter means a straight line passing from side to side through the center of a body or figure, especially a circle or sphere. The area means what the extent or measurement of a surface or piece of land. So area means inside so all you need to do is  just to divide each side by knowing what 20/4 is and that = 5 meters