JEE Main2012MathematicsProperties of TrianglesActual
In a PQR , if 3 P +4 Q =6 and 4 Q +3 P =1 , then the angle R is equal to
Options
- A5 6
- B6
- C4
- D3 4
Correct answer
B. 6
Step-by-step solution
3 P+4 Q=6 (1)4 Q+3 P=1 (2) From (1) and (2) P is obtuse. (3 P+4 Q)^2+(4 Q+3 P)^2=37 9+16+24( P Q+ P Q)=37 24 (P+Q)=12 (P+Q)= 1 2 P+Q= 5 6 R= 6