Finding unknown mass with tension

[x__o]

Homework Statement

so my teacher assigned me a to find the mass of this key without a scale using strings at whatnot.

Homework Equations

The Attempt at a Solution

i tried setting up the system like this:

____ceiling_____
\ /
\/
O
|
[Key]

and i can't seem to find it because i can't find tension.

T2=mg and Ty=T1sinθ

2T1y=T2

 

[hage567]

What about the x components of the tensions? You need to find both the x and components for both strings. I'm assuming there is two strings there.