h B Q 9.2.1 Prove that AD =~ BC in Construction Problem 9.2.1. Construction Problem 9.2.1 (1.2). Given a point A and a segment BC, construct a point D such that AD = BC. Solution. If A = B, take D = C. Assume A # B. Construct a point E such that AABE is an equilateral triangle (previous construction). Draw the circle with center B and radius BC. Let F be the point at which the ray EB meets a. Draw the circle g with center E and radius EF. Let D be the point at which the ray EA crosses B. (See Figure 9.2.) The proof that AD = BC is left as an exercise (Exercise 9.2.1). u