Question

Solve for r:d=rR2/R2+R1

Answer 1

Step-by-step explanation: this involves change of subject of formula

Given d=rR2/R2+R1

d-R1=rR2/R2

Crosss multiplying

( d-R1)R2=rR2

Divide both sides by R2

r=d-R1

Answer 2

d=rR2/(R2+R1)
d(R2+R1)=rR2
[d(R2+R1)]/R2 = r