Answer:
CD = (3/2)√2
Step-by-step explanation:
All the triangles are similar isosceles right triangles, so the hypotenuse in each case is √(1²+1²) = √2 times the length of the corresponding legs. BC is the hypotenuse of ΔBCD, so leg CD is that length divided by √2.
CD = BC/√2 = 3/√2
CD = (3/2)√2