MHT CET202616 April 2026Morning ShiftMathematicsProperties of TrianglesActual
With usual notations in ABC, if b ^2 C 2 + c ^2 B 2 = 3a 2 then
Options
- Aa, b, c are in A.P.
- Ba, c, b are in A.P.
- Cb, a, c are in A.P.
- Da, b, c are in G.P
Correct answer
C. b, a, c are in A.P.
Step-by-step solution
Given b ^2 C 2 + c ^2 B 2 = 3a 2 Using the half-angle formula ^2 2 = 1 + 2 , the equation becomes: b ( 1 + C 2 ) + c ( 1 + B 2 ) = 3a 2 Multiplying by 2 on both sides: b + b C + c + c B = 3a Rearranging the terms: b + c + (b C + c B) = 3a Using the projection formula a = b C + c B : b + c + a = 3a b + c = 2a This condition implies that b, a, c are in A.P. Answer: b, a, c are in A.P.