I need help with math!! it’s due tomorrow and it’s a test grade! help please! no links please!

The given graph represents growth, a half-parabola behavior.
We have to find the ratio of change
[tex]r=\frac{f(b)-f(a)}{b-a}[/tex]Where a = 0, f(a) = 100, b = 4, f(b) = 500.
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