Question 366328
anytime you have a quadratic equation such as the one you pose
there are several ways to answer your question.
--
1) complete the square
h={{{-0.043d^2+2.363d=-0.043(d^2-55d+(55/2)^2-(55/2)^2)=-0.043(d-55/2)^2+32.51}}}
--
So the maximum height is 32.51 meters when d=55/2=27.5 meters
==
Another way to figure this out is to remember that a quadratic equation ofthe form {{{y=ax^2+bx+c}}} has its vertex at x=-b/(2a) and that the vertex (minimum if a>0 or maximum if a<0) is found by substituting x=-b/(2a) back into {{{y=ax^2+bx+c}}} 
--
so in your equation a=-0.043 and b=2.363
since a<0 the vertex is a maximum and its found at x=-2.363/(2*(-0.043))=27.5
so substitute x=27.5 in {{{y=-0.043x^2+2.363x}}} yielding
y={{{-0.043*27.5^2+2.363*27.5}}}=32.46 
--
some rounding error between this method and the previous method, otherwise the same answer.