



 
Hi Jeffrey, I drew a diagram on the Cartesian plane with the origin 10 m below the lowest point of the cable. Since the cable forms a parabola its equation is $y = a x^2 + b x + c$ for some numbers $a, b$ and $c.$ Since you know $(0, 10)$ is on the graph of the parabola you have $10 = a \times 0^2 + b \times 0 + c$ you know that $c = 10.$ You also know that $(100,40)$ and $(100, 40)$ are on the graph so substitution gives you two equations to solve for $a$ and $b.$ Penny  


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