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Cogito

Geometry · Chapter 1 · Lesson 1

Practice Worksheet

Definitions, Postulates, and Proof

What counts as an argument.

8 problems · about 19 minutes · G-CO.A.1, G-CO.C.9

NameDate

Figure — use these to answer the problems

An angle is defined by two rays sharing an endpoint. That definition is the starting point.
030609012015018060°
Angle60
Figure 1

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. Supplementary to 118°?

    Answer

  2. What must every line of a proof have?

    • A reason.
    • A diagram.

  3. Complementary to 32°?

    Answer

  4. Supplementary to 91°?

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. Is "point" a defined term?

    • No. It is undefined.
    • Yes.

  2. Two vertical angles, one is 47°. The other?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

2 problems

  1. The Supplement

    Two supplementary angles, one is 55°. What is the other?

    Answerdegrees

  2. The Vocabulary

    A statement accepted without proof is called what?

    • A postulate.
    • A theorem.