If an external point of a circle is at a distance equal to the diameter of the circle

Let the radius of the circle be r. Then the line from the external point through the center of the circle which extends to the far point on the circle has length 3r .By the tangent - secant theorem

t^2 = 3r * r = 3r^2 ( where t is the length of the tangent).

So t = √(3r^2) = √3r answer.

q=amount of quarters

d=amount of dimes

0.10d+0.25q=4.20

2d=q

comment "egg" if you're coming here from DeltaMath