A quadratic function?

Like in the form y = ax^2 +bx +c ?

That will pass the point (50.8,120)

Tweak the "a" so that the graph will pass through (50.8,120)?

Okay, nothing will stop you from using the quadratic y = ax^2.

You can forget about the bx and c....since they are not specifically called for.

So,

y = ax^2

120 = a(50.8)^2

a = 120 /(50.8)^2

a = 0.0465

That is it.