# Building a Polar Point From Cartesian Coordinates

**00:00**
Building a Polar Point From Cartesian Coordinates. For a more elaborate example of providing multiple constructors using class methods, let’s say you have a class representing a polar point in a math-related application.

**00:15**
You need a way to make your class more flexible so that you can construct new instances using Cartesian coordinates as well. On-screen, you can see how to write a constructor to meet this requirement.

**00:50**
`.from_cartesian()`

takes two arguments representing a given point’s `x`

and `y`

Cartesian coordinates. Then the method calculates the required `distance`

and `angle`

to construct the corresponding `PolarPoint`

object.

**01:08**
Finally, `.from_cartesian()`

returns a new instance of the class.

**01:36**
On-screen, you can see the class working using both coordinate systems. First you create a point using polar coordinates, and then one using Cartesian coordinates.

**01:55**
In these examples, you use the standard instantiation process and your alternative constructor, `.from_cartesian()`

, to create `PolarPoint`

instances using conceptually different initialization arguments.

**02:10**
In the next section of the course, you’ll take a closer look at the use of multiple constructors in Python’s built-in and standard-library classes.

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