geometry
posted by carson .
In right triangle ABC, angle C=90 degrees, AC = 3 and CB =4. If D is on segment AB and DB = 2, find the distance from D to C.

AB is the hypotenuse, the length of which is sqrt (3^2 + 4^2) = 5 since this is a right triangle. CD is a line from the right angle corner to a point on the hypotenuse. You can gets its length by applying the law of cosines on smaller triangle BCD. You know the lengths of BD and BC and the included angle B cosine (which is 4/5)