If a tangent segment and a secant segment are drawn to a circle from an exterior, then the square of the length of the tangent segment is equal to the product of the lengths of the secant segment and its external secant seginent. What is the measure of a if b = 2 cm and c = 8 cm? 2 cm c. 8 cmr b. 4 cm d. 16 cm Solution: a = b c