One Step Geometry Proofs

Why is it helpful to sketch a diagram when writing certain proofs?

• To make the proof look more professional

• To waste time

• To visualize the problem and understand the relationships between geometric figures

• To confuse the reader

When might you use the Subtraction Property of Equality in geometry?

• To justify a step in a proof involving multiplying both sides of an equation.

• To justify a statement in a proof involving subtracting from both sides of an equation.

• To prove the Angle Subtraction Theorem

• As a "statement" in a proof

What might you use the Definition of Complementary Angles for in a geometric proof?

• To prove the Vertical Angles Congruence Theorem

• To justify the statement that two complementary angles add up to 180 degrees.

• To explain the relationship between angles

• To justify the statement that two complementary angles add up to 90 degrees.

What might you use the Definition of Supplementary Angles for in a geometric proof?

• To justify the statement that two supplementary angles add up to 180 degrees

• To justify the statement that two supplementary angles add up to 90 degrees

• To explain the relationship between all adjacent angles

• To make geometry more difficult

Fill in the blanks to complete the geometric proof:

• ∠PQR = 38; B: Definition of Complementary Angles; C: Subtraction

  Property of Equality

• ∠PQR = 38; B: Definition of Supplementary Angles; C: Reflexive Property

• ∠PQR = 38; B: Definition of Vertical Angles; C: Transitive Property

• ∠PQR = 38; B: Definition of Complementary Angles; C: Substitution

What is the "reason" for step 5 of the proof?

• Angle Bisector Theorem

• Reflexive property

• CPCTC Theorem

• Proof

How can you prove step #2?

• Vertical angle theorem

• Subtraction property of equality

• Transitive property of congruence

• Definition of supplementary angles

How can you prove step #5?

• Vertical angle theorem

• Subtraction property of equality

• Transitive property of congruence

• Definition of supplementary angles

What reason justifies statement #2?

• Definition of Midpoint

• Transitive Property

• Addition Property

• Segment Addition Postulate

• Substitution Property

How can you prove step #4?

• Vertical angle theorem

• Subtraction property of equality

• Transitive property of congruence

• Definition of supplementary angles