# Net Magnetic Field at the Center of a Loop and X Distance Away From a Wire

#### BornSurvivor

1. Homework Statement
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-prn1/553004_1959186995753_1725123128_934768_456680196_n.jpg [Broken]
In case the words are too small:
I2= 6.61I1
The net magnetic field at center of loop is 0.
I'm looking for the radius of the loop

2. Homework Equations
for straight wire: B=(u0*I)/(2$\pi$*r)
for loop: B= (u0*I)/(2*r)

3. The Attempt at a Solution
So, since the two magnetic fields are perpendicular to each other: √(B12+B22)=0
I tried to find H in terms of R by using the right hand rule. I2/I1=(B2*H*$\pi$)/(B1*R) so H= -(6.61R/$\pi$)
But now I'm stuck, and I don't know if my work so far is even right.

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