Make a Circle with OOP

Your task is to create a Circle constructor that creates a circle with a radius provided by an argument. The circles constructed must have two methods getArea() (PI*r^2) and getPerimeter() (2*PI*r) which give both respective areas and perimeter (circumference).

For help with this class, I have provided you with a Rectangle constructor which you can use as a base example.

Examples

let circy = new Circle(11)
circy.getArea()

// Should return 380.132711084365

let circy = new Circle(4.44)
circy.getPerimeter()

// Should return 27.897342763877365

Notes

Don't worry about floating point precision - I've factored in the chance that your answer may be more or less accurate than mine. This is more of a tutorial than a challenge so the topic covered may be considered advanced, yet the challenge is more simple - so if this challenge gets labelled as easy, don't worry too much.