To convert from rectangular coordinate (x, y) to polar coordinate (r, θ).
r is given by the square root of the sum of the squares of the rectangular coordinate.

and θ is given by the arctan of the ratio of y to x.

Example:
To convert rectangular coordinate (3, 4) to polar coordinate

Therefore, rectangular coordinate (3, 4) = polar coordinate (5, 53.13°)
we know the blue and white paints are on a 1.5 : 5 ratio, thus, if we have a total of 16.25 gallons of paint to be split along that ratio, we can simply divide 16.25 by (1.5+5) and distribute accordingly.

If you do 22÷9 and see the hole number: 2. Then do 2 x 9 and you get 18. Now do 22-18 and you get 4. So do 2 4/9. Always have the denominator stay the same.