Finding spring constant k from launch distance and height

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EDIT: I just found the homework board, mods: don't bother moving this thread, just delete it. Thanks

We had a lab where we launch springs with an unknown k constant to a target 2.01m away and 0.22m high. We also know the angle at which we shot the spring.

We need to find the k constant of the spring, so my question is, does the kinetic energy matter?

Will the equation be:

Eg + Ee = Eg + Ek (The spring had gravitational potential as it was launched a bit higher than the reference position (the table)

or

Eg + Ee = EgThanks.

 

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If I did the Eg + Ee = Eg method, then my k constant turned out to be 2.752 N/m.

The spring's length at equilibrium is 0.04m; the spring is quite tiny.

Does this k constant seem to small?

 

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Also, using F= kx, the force contained in the spring when x = 0.035m, is 0.09632N

Are these values too small, which could possibly hint the method I tried is wrong?