Finding the distance between two circles

Question

I'm trying to figure out how to get the distance from two circles relative to the corners of their square container boxes. I need some help with the maths here.

How can I work out the number of pixels for the line marked with a question mark?

Appreciate the help as always.

Answer 1

tldr: Calculate the distance between each circles center point, then subtract the radius' of each circle from that.

For the purpose of a demonstration, we will assume the following:

• The 200px diameter (r1 = 100) circle is at the (x, y) coordinates of (0, 0), and
• the 100px diameter (r2 = 50) circle is at (x, y) coordinates of (150, -150).

Given that the distance between their centers is:

To find the distance between their boundaries, we subtract the radius of each circle from the distance between their centers.

This leaves us with the equation:

sqrt((x2 − x1)^2 + (y2 − y1)^2) − (r2 + r1)

Inserting your values into the above gives:

sqrt((150 − 0)^2 + (-150 − 0)^2) − (100 + 50) = 62.132034356px

Answer 2

Do you have the middle point of each circles? If you do, first calculate the distance from the centre of circles.

distance² = center1² + center2²

Then, you will need to minus the radius of both circles. In your case, it will be 150 (100 + 50)