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.)
:
let x = cross sectional area of 10 ohm wire
:
An inverse, ratio equation
{{{x/1250}}} = {{{7/10}}}
Cross multiply
10x = 7*1250
10x = 8750
x = {{{8750/10}}}
x = 875 cmil cross sectional area