Exercise 76 Page 42

By using Fact 1 and Fact 2 we can define what a square is and also what makes it a rectangle. Fact #1: &A square has four sides &of equal length Fact #2: &A square is a rectangle because & it has four right angles From Fact 2 we know that it is the square's angles that cause us to classify it as a rectangle. Now, let's look at Fact 3. Fact #3: &A rhombus also has four sides &of equal length Fact 3 does not say anything about the angles of the rhombus, which is what we use to define a square as a rectangle. Therefore, we cannot conclude that a rhombus is a rectangle.