# Geometry

posted by
**DANIELLE** on
.

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