Externally Tangent Circles

Description

Two circles of non-equal radius, both in the same plane, are said to be tangent to each other if they meet at only one point.
Two circles are externally tangent if the distance between their centres is equal to the sum of their radii.

Related formulas

Variables

x1X-coordinate of the center of one circle (dimensionless)
x2X-coordinate of the center of other circle (dimensionless)
y1Y-coordinate of the center of one circle (dimensionless)
y2Y-coordinate of the center of other circle (dimensionless)
r1Radius of one circle (dimensionless)
r2Radius of other circle (dimensionless)