SOLUTION: One wire has a cross-sectional area of 1,250 cmil and a resistance of 7 ohms. A second piece of wire, identical except for cross-sectional area, has a resistance of 10 ohms. De

Algebra ->  Proportions  -> Lessons -> SOLUTION: One wire has a cross-sectional area of 1,250 cmil and a resistance of 7 ohms. A second piece of wire, identical except for cross-sectional area, has a resistance of 10 ohms. De      Log On


   



Question 312509:
One wire has a cross-sectional area of 1,250 cmil and a resistance of 7 ohms. A second piece of wire, identical except for cross-sectional area, has a resistance of 10 ohms. Determine what the cross-sectional area of this second wire is. (Cross-sectional area and resistance are inversely proportional.)

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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One wire has a cross-sectional area of 1,250 cmil and a resistance of 7 ohms.
A second piece of wire, identical except for cross-sectional area, has a resistance of 10 ohms.
Determine what the cross-sectional area of this second wire is.
(Cross-sectional area and resistance are inversely proportional.)
:
let x = cross sectional area of 10 ohm wire
:
An inverse, ratio equation
x%2F1250 = 7%2F10
Cross multiply
10x = 7*1250
10x = 8750
x = 8750%2F10
x = 875 cmil cross sectional area