How can u show that two objects are proportional using a graph

You can show that (y) is proportional to (x) by writing:



This would mean that:



Whereby (k) would be the constant of proportionality.

This value can be an element of a real number.

k∈R

What are real numbers?

Integers, rational numbers and irrational numbers.

Example of a graph which would show that 2 objects are proportional:

y=2x

There is a directly proportional relationship, and an indirect proportional relationships.

A directly proportional relationship graph will always be a linear line.
The graph of a indirectly proportional will be a curve.

Directly proportional equation: y = kx
Indirectly proportional equation: xy = k

where k is the constant of proportionality.

I have attached a graph of them so you can better understand it :)