Question

Gordon is writing a proof of the theorem stated below.

Theorem: The sum of interior angles of a triangle is 180°.

He first drew the figure shown below.



Which theorem will he most likely use in the proof?
Answer
A linear pair of angles is supplementary.
Supplements of congruent angles are congruent.
If two angles of a triangle are congruent, the sides opposite these are congruent.
If two sides of a triangle are congruent, the angles opposite these sides are congruent.

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Answer 1

Does it mention any other proofs used beforehand?

Answer 2

let me look!

Answer 3

alright

Answer 4

nope!

Answer 5

alright, just checking, it looks like you'll use the idea that "Supplements of congruent angles are congruent." to start the proof off


Basically, if x+y = 180 and y = z, then x+z = 180. This idea can be extended and can be used to show that the sum of angles 1 through 3 is 180 degrees.

Answer 6

oo ok i understand! thanks!!

Answer 7

that's great, yw