Because 843,000 is closer to 840,000 than 850,000
The line is called the directrix. Here we have a vertical directrix, so a parabola sideways from usual.
Geometry is best done with squared distances. The squared distance from an arbitrary point (x,y) to the vertical line x=2 is

We equate that to the squared distance of (x,y) to the focus (-2,0):



We could call that done. A more standard form might be
A rectangular prism is a cuboid so volume of cuboid is base area x height which is 5x5x12=300
volume of pyramid is 1/3 x base area x height = 5x5x6x1/3=50 thus volume outside pyramid and inside cuboid is 300-50=250
cos(30)=x/8
Rewrite the equation as
x/8=cos(30)
Multiply both sides of the equation by
8
.
8
⋅
x/8=8⋅cos(30)
Simplify both sides of the equation.
Tap for more steps...
x=4√3
The result can be shown in multiple forms.
Exact Form:
x=4√3
Decimal Form:
x=6.9282032