Tangent Coins

Here are two ordinary coins, a quarter and a nickel. I am going to draw an external tangent from the quarter to the dime. I will be showing how drawing a line from the center of one of the coins (or circles in this case) to the point of tangency will form a right angle.

It is clear that the angle drawn from the center of the dime to its point of tangency (on the tangent shared with the quarter) is roughly 90 degrees, thus proving that any line drawn from the center to a point of tangency creates a 90 degree angle.

It is also seen here that the line from the point of tangency to the center creates a 90 degree angle.

(~DM5)