McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. Rhombi and Squares
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Exercise 47 Page 519

Recall that a square is a rectangle with four sides that are congruent.

Type of Statement Statement True or False?
Original If a quadrilateral is a square, then it is a rectangle. True âś“
Converse If a quadrilateral is a rectangle, then it is a square. False *
Inverse If a quadrilateral is not a square, then it is not a rectangle. False *
Contrapositive If a quadrilateral is not a rectangle, then it is not a square. True âś“

For explanation see solution.

Practice makes perfect

Let's begin with recalling that a square is a rectangle with four sides that are congruent. Now we will take a look at the given statement. If a quadrilateral is a square, then it is a rectangle. As we recalled, a square is a special case of rectangle that has all congruent sides. This means that each square is a rectangle at the same time. Therefore, this statement is true.

Converse Statement

To create a converse statement, we should exchange a square and a rectangle.

Original Statement Converse Statement
If a quadrilateral is a square, then it is a rectangle. If a quadrilateral is a rectangle, then it is a square.

Since not all rectangles have congruent sides, the converse statement is false.

Inverse Statement

Next, to create an inverse statement we should add not to each part of the statement.

Original Statement Inverse Statement
If a quadrilateral is a square, then it is a rectangle. If a quadrilateral is not a square, then it is not a rectangle.

Let's notice that a quadrilateral with two pairs of congruent sides and all right angles is rectangle, but it is not necessarily a square, which has all four congruent sides. Therefore, the inverse statement is false.

Contrapositive Statement

Finally we will create a contrapositive statement. To do this, we should exchange a square and a rectangle, and we should add not to each part of the statement.

Original Statement Contrapositive Statement
If a quadrilateral is a square, then it is a rectangle. If a quadrilateral is not a rectangle, then it is not a square.

A quadrilateral needs to satisfy all conditions of rectangles to be a square. Therefore, if it is not a rectangle, it cannot be a square. This means that this statement is true.