perimeter or rectangle= 2l+2w
Surface area of a cylinder=2(pi)r^2+2(pi)r
Volume of a triangular prism=Bh
Area of a circle=(pi)r^2
Answer:
Manufacturers has to produce 63 DVD/Blu-Ray players to achieve a minimum cost of $644
Step-by-step explanation:
The cost equation is given as:

This is a quadratic equation in general form, which is:

Matching, we can say:
a = 0.04
b = -5
c = 800
The minimum occurs at 
and the minimum value would be to place that "x" value into the equation.
First, we find the minimum using values of a and b:

Plugging this into original, we get:

Rounding off to nearest whole number, we can say:
Manufacturers has to produce 63 DVD/Blu-Ray players to achieve a minimum cost of $644
Step-by-step explanation:
tan30° = Height of person / (Distance away from river bank + river's width) = 1/√3.
Therefore 1.6m / (2m + x) = 1/√3
By cross multiplication, 1.6√3 = 2 + x.
Hence, x ≈ 0.77m.