Question

Given: In triangle QRS, angleR=30degrees. Prove:angleS is not equal to 150degrees.

Answer 1

write an indirect proof

Answer 2

indirect proof..i mean if angle s=150,,the|dw:1372139783373:dwn

Answer 3

Proof by contradiction
1. Given triangle QRS, angleR=30degrees.
2. Assume angleQ=150degrees.
3. Then the sum of the angles are: angleQ + angle R + angle S = 150 + 30 + angleS = 180 + angle S > 180 (since angleS > 0).
4. The sum of the angles being greater than 180degrees contradicts the theorem that states the angles of every triangle add to 180degrees.
5. Therefore our assumption that angleQ=150degrees must be false, and we conclude that angleQ does not equal 150degrees.