The angle of depression from a hot air balloon to a person on the ground is 36. When the person steps back 10 feet the new angle of depression is 25°. If the person is 6 feet tall, how far above the ground is the hot air balloon to the nearest foot?

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204