Writing indirect proofs.
Can someone please check for me. I am not sure If this is correct.Thanks much
Given: triangle ABC angle B=120 degree
Proof: Triangle A does not equal 60 degree
Plan: Using an indirect proof, using the paragraph method
My answer.
Assume temporarily that Measure angle A = 60. Then measure angle C=60,
and measure angles A+B+C=180= 60+B+60=180. Therefore the temporary assumption that measure angle A=60 is false. It fallows that measure angle 60 does not equal 60 degrees
I think your answer is correct.
Your answer is almost correct, but there are a couple of minor errors. Here's the correct version:
Assume temporarily that Measure angle A = 60 degrees. Then we know that Measure angle B = 120 degrees, and therefore Measure angle C = 180 - 60 - 120 = 0 degrees. However, angles in a triangle must always add up to 180 degrees, so the temporary assumption that Measure angle A = 60 degrees is false. Therefore, we can conclude that Measure angle A does not equal 60 degrees.
In an indirect proof, you assume the opposite of what you want to prove, and then you show that this assumption leads to a contradiction or an impossible situation. In this case, you assumed that Measure angle A = 60 degrees, and you showed that it leads to Measure angle C = 0 degrees, which contradicts the fact that angles in a triangle must add up to 180 degrees.
Well done on using the paragraph method to clearly explain your reasoning!