Not sure. I’m not good with graphs
Well,
Given that
,
We can rewrite the equation like,

Now use,
which implies that 
That means that,

By def
therefore 
So the fraction now looks like,

Which is equal to the identity,

Hope this helps.
r3t40
The correct fraction is 60/10 or 6 rows of ten
10/60= 1/6 not a whole number
Check the picture below, that's a parabolic graph of a quadratic equation with a negative leading coeffficient, like this one, the one in the graph is just for initial velocity, but, the highest point is at the vertex for any of these parabolas.
and this one is not exception, so where's the vertex? what's A or the y-coordinate when the vertex is reached?, well, let's check.

so, that's the vertex, and when the width is that much, the Area reaches a maximum of that much.