Reasoning in Geometry Review

Refer to the following statement: "If a polygon is a quadrilateral, then it is a trapezoid." What is the converse of this statement?

• If a polygon is not a quadrilateral, then it is not a trapezoid.

• If a polygon is not a trapezoid, then it is not a quadrilateral.

• If a polygon is a trapezoid, then it is a quadrilateral.

• A rectangle is also a quadrilateral.

What is the inverse of this statement?

• If the polygon is not a quadrilateral, then it is not a trapezoid.

• If the polygon is not a trapezoid, then it is not a quadrilateral.

• If the polygon is a trapezoid, then it is a quadrilateral.

• A rectangle is also a quadrilateral.

What is the contrapositive of this statement?

• If a polygon is a trapezoid, then it is a quadrilateral.

• If a polygon is not a quadrilateral, then it is not a trapezoid.

• If a polygon is not a trapezoid, then it is not a quadrilateral.

• A rectangle is also a quadrilateral.

Rewrite the statement as a conditional statement. "The sum of the angles of a triangle is 180."

• If the sum of the angles of a triangle, then 180.

• If a figure is a triangle, then the sum of the angles is 180.

• If a figure sums angles, then the triangle is 180.

Refer to the following statement: "If a polygon is a quadrilateral, then it is a trapezoid." What is the inverse of this statement?

• If the polygon is not a quadrilateral, then it is not a trapezoid.

• If the polygon is not a trapezoid, then it is not a quadrilateral.

• If the polygon is a trapezoid, then it is a quadrilateral.

• A rectangle is also a quadrilateral.

Refer to the following statement: "If a polygon is a quadrilateral, then it is a trapezoid." What is the contrapositive of this statement?

• If a polygon is a trapezoid, then it is a quadrilateral.

• If a polygon is not a quadrilateral, then it is not a trapezoid.

• If a polygon is not a trapezoid, then it is not a quadrilateral.

• A rectangle is also a quadrilateral.

If angles are congruent, then the measures of the angles are equal. Identify the contrapositive.

• If the measures of the angles are equal, then the angles are congruent.

• If angles are not congruent, then the measures of the angles are not equal.

• If the measures of the angles are not equal, then the angles are not congruent.

• If the angles are not congruent, then the measure of the angles are equal.

The statement "an angle is a right angle if and only if its measure is 90^o" is an example of what?

• Deductive reasoning

• A conjecture

• A biconditional

• A counterexample

Determine the converse of the statement: "If angles are congruent, then the measures of the angles are equal."

• If the measures of the angles are equal, then the angles are congruent.

• If angles are not congruent, then the measures of the angles are not equal.

• If the measures of the angles are not equal, then the angles are not congruent.

• If the angles are not congruent, then the measure of the angles are equal.

Which statement is a valid conclusion based on the argument? If a polygon is a regular pentagon, then it has exactly five congruent angles. The polygon is a regular pentagon.

• Therefore, the polygon is a rectangle.

• Therefore, the polygon is a regular quadrilateral.

• Therefore, the polygon has exactly five congruent angles.

• Therefore, the polygon has congruent sides.