The Lagrangian is

It has critical points where the first order derivatives vanish:



From the first two equations we get

Then

At these critical points, we have
(maximum)
(minimum)
Answer:
The missing segment length is 20.
Step-by-step explanation:
2 is multiplied by 4 to get to 8, so 5 must be multiplied by 4 to get to 20.
The closest would be 7
7x7 is 49 and that is the closest
In your question that ask to calculate the area of one of the tiles if a semicircular archway in the front of the garden is using 8 congruent granite tiles and the area of one of the tiles is 2.9ft ^2. I hope you are satisfied with my answer and feel free to ask for more.

We know that
.
Solve using cross multiplication of the last two fractions. I will use
to represent the width of the rectangle. 
Multiply. 
Divide both sides of the equation by
. 