The midpoint is: (-4.5,8.5)
<span>90/x=100/18</span>
<span>(90/x)*x=(100/18)*x - </span> multiply both sides of the equation by x
<span>90=5.55555555556*x - </span>divide both sides of the equation by (5.55555555556) to get x
<span>90/5.55555555556=x </span>
<span>16.2=x </span>
<span>x=16.2</span>
<span>18% of 90=16.2
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