How to Calculate Current in a Solenoid with Given Field and Dimensions?

[PeachBanana]

Homework Statement

A 27.0-cm long solenoid 1.25 cm in diameter is to produce a field of 0.215 T at its center. How much current should the solenoid carry if it has 900 turns of the wire?

Homework Equations

B = μIN / l

The Attempt at a Solution

Why am I given the diameter plus the length? Everything else is obvious except this concept. I thought l would equal = 0.27 m. Should I add 0.625 + 0.27 m because the magnetic field is produced at the center?

 

[SHISHKABOB]

you don't need the diameter at all for this problem ;)

 

[PeachBanana]

Aha! Extra information! Thank you.