Static equilibrium - quarry crane

[ch010308]

Homework Statement

A quarry crane is used to lift massive rocks from a quarry pit. Consider the simplified model of such a crane shown in the figure. The ends of two poles are anchored to the ground at the same point (point O). From this point, one pole rises vertically and the second pole rises at an angle. The vertical pole has its free end connected to the ground via an unstretchable, massless rope labeled rope 1. A second rope, labeled rope 2, connects the free ends of the two poles. The angle between the tilted pole and rope 2 is θ. Both poles have length and can be considered massless for the purposes of this problem. Hanging from the end of the second pole, via rope 3, is a granite block of mass m.

Throughout this problem use g for the magnitude of the acceleration due to gravity.

Find T₂, the tension in rope 2.

Homework Equations

At static equilibrium, sum of torque=0, sum of forces = 0.

The Attempt at a Solution

I think I need to use sum of torque (about point O??) but how? I don't understand the qns/ diagram... Please help! Thanks:)

 

[LowlyPion]

The same problem discussed here.
https://www.physicsforums.com/showthread.php?t=301645

 

[ch010308]

I tried to derive the answer from the hints given in that thread but I still got it wrong. :(

There's also another part to the question:
Find T₁, the tension in rope 1.

Please help!