Help needed in triangles.

Let ABC be a triangle in which angle A = 60 degrees. Let BE and CF be the bisectors of the angles B and C, with E on AC and F on AB. Let M be the reflection of A in the line EF. Prove that M lies on BC.

How do I start?

4 Answers

49
Subhomoy Bakshi ·

General Inferences!!

E is equidistant from AB and AC

F is equidistant from AC and BC

perp from E to AB (EX), perp from F to AC (FY) and perp from A to EF (AZ) are concurrent!

B+C=120°

aur dikha toh likh dunga!! :P

1
swordfish ·

F is equidistant from AC and BC
Is this some property of angle bisectors?

perp from E to AB (EX), perp from F to AC (FY) and perp from A to EF (AZ) are concurrent!

How did you infer that they are concurrent?

B+C=120°

I did not get how you concluded the answer from this :|

71
Vivek @ Born this Way ·

How did you infer that they are concurrent?

Perpendicular bisectors are concurrent!

1
swordfish ·

@Vivek - If you understood what subho meant can you explain the rest -
F is equidistant from AC and BC & B+C=120° ( I know how they sum up to 120 but how do you infer from this that the image of A lies in BC

Your Answer

Close [X]