The area of the plate

Problem

A round plate measures diameter centimeters from edge to edge, straight through the center. Write a function that returns how much surface it covers. The area of a circle is pi times the radius squared, and careful: the formula asks for the radius, not the diameter.

Use 3.1416 for pi and return the result rounded to two decimals. A plate with a diameter of 1 measures 0.79, and one of 10 measures 78.54.

Examples

• 10 → 78.54

• An odd diameter

  7 → 38.48

• The smallest plate

  1 → 0.79

Besides these, the challenge has hidden tests that are revealed when you submit your solution.

You start with this

def plate_area(diameter):
    pass

function plateArea(diameter) {
}