We are given a rectangle;
Key ideas in solving these problems are;
1. The opposite sides of a rectangle are congruent
2. The diagonals of a rectangle bisect each other.
From this equation;
a. The measure of side CD is 18cm
b. The measure of diagonal BD is 30cm
c. The perimeter of triangle CDE is CD + DE + EC = 18 + 15 + 15 = 48 cm
