Here 'a' corresponds to 0.
Now there are two possibilities for 'r' & 't'
Case 1.
They are on the same side to the right of 'a'
In that case 'r' corresponds to 5 & 't' corresponds to 7.
The midpoint of 'r' and 't' shall be 
Case 2.
Both are on the left of 'a'.
In that case 'r' corresponds to -5 & 't' corresponds to -7
The midpoint shall be 
Case 3.
'r' in on the right of 'a' and 't' is on the left of 'a'
So 'r' corresponds to 5 and 't' corresponds to -7
The midpoint shall be 
Case 4.
'r' is on the left of 'a' & 't' is on the right of 'a'.
'r' corresponds to -5 & 't' corresponds to 7
The midpoint shall be 
The possible coordinates of the midpoints of rt are 6, -6, 1, -1.
The general formula for the lateral surface area of a regular pyramid is:
Where:
p=perimeter of a base
l=slant height
a.
a=3ft
l=4ft
p=5*a=5*3=15ft
b.
a=2.5ft
l=4ft
p=6*a=6*2.5=15ft
c.
a=1.9ft
l=4ft
p=8*a=8*1.9=15.2ft
d.
Based on a lateral surface area the blue umbrella is best choice. But, the best umbrella overall is the one with the greatest base area. General formula for regular polygon is:
For pentagon:
A=15.48ft^2
For hexagon:
A=16.24ft^2
For octagon:
A=17.43ft^2
Blue umbrella is still best choice.
New York City is around 3,000 miles away from London
Answer:
14 songs on the final CD.
For the center of this circle the right choice will be choice B. (-21,-19)
and its radius sqrt849 = 849^(1/2) so choice B. is right for this too
hope this will help you
