Posted by **DANIELLE** on Tuesday, June 12, 2007 at 1:14pm.

Given: in triangle ABC, angle B= 120 degrees

Prove: angle A does not= 60 degrees

Plan: use indirect proof

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 A does not equal 60 degrees.

excellent.

## Answer this Question

## Related Questions

- Geometry - Writing indirect proofs. Can someone please check for me. I am not ...
- Algebra - In triangle ABC, the measure of angle B is 8 degrees more than three ...
- algebra. - problems about angles: Hi. I needed help on some problems for the ...
- College Math - In a certain triangle the measure of one angle is triple the ...
- math - in a triangle, the measure of the first angle is twice the measure of the...
- ALGEBRA - In triangle ABC, the measure of angle B is 27 degrees more than three ...
- Geometry HELP!! - I need help with my geometry hw, i need to now wat the ...
- Geometry - Angle ABC and ange DBE are vertical angles,the measure of angle ABC...
- Geometry - Angle ABC and ange DBE are vertical angles,the measure of angle ABC...
- geometry - Two lines intersect to form two pairs of vertical angles.Angle 1 with...

More Related Questions