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Solve this formula for r.  Simplify your answer. `E/d = (R + r)/r` Make sure you use...

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kristenmarieb... | Student, Grade 10 | Valedictorian

Posted September 16, 2013 at 5:19 PM via web

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Solve this formula for r.  Simplify your answer.

`E/d = (R + r)/r`

Make sure you use parentheses around any polynomials in the numerator and/or denominator.

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tiburtius | High School Teacher | (Level 3) Associate Educator

Posted September 16, 2013 at 5:26 PM (Answer #1)

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`E/d=(R+r)/r`

Now multiply whole expression by `dr.`

`Er=Rd+rd`

`Er-rd=Rd`

`r(E-d)=Rd`

Now divide whole expression by `(E-d).`

`r=(Rd)/(E-d)`  <-- Your solution.

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