Implement Class Shape

Shape

ShapeAreaPerimeter
Squarea24a
Rectanglea * b2 (a + b)
Trianglesqrt( (p - a) * (p - b) * (p - c))
p = (a + b + c)/2
a + b + c
Ellipseπ*a*bπ(a + b)
Circleπ*r22πr