6th grade math
First, you set it up: 4/n=1/2 then, multiply n to both sides so: (n)(4/n)=(1/2)(n) the n cancels out on one side so it should look like: 4=1/2(n) now you just solve for n: 4(1/2)=n so n=2
Find the inverse of cosA, so cos-(.11)=83.7 I hope it's right!
I believe that is right; it looks like single replacement because: AB+C-->AC+B
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