9514 1404 393
Explanation:
The quadrilateral will be a parallelogram if the diagonals bisect each other. That will be the case if the sums of their end-point coordinates are the same.
A + C = (-3, 6) +(9, -9) = (6, -3)
B + D = (6, 0) +(0, -3) = (6, -3)
Both diagonals have their midpoint at (3, -1.5), so the diagonals are mutual bisectors. The figure ABCD must be a parallelogram.
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The midpoint of AC is (A+C)/2 = (6, -3)/2 = (3, -1.5).
No 3 should be inch 6 should be feet
| Formula for the volume of a cone: 
Answer:
C ≤ 11
Step-by-step explanation:
c − 5.5 + 5.5 ≤ 5.5 + 5.5
add 5.5 to both sides
if one customer shows up, and she buys one song, that's $1.29, if she doesn't buy anymore, then that's the charge.
the first song is always at a full price, and after that, to encourage buying, the next ones are just 99 cents, let's see how it goes after a few songs purchases.
1 song.........................$1.29
2 songs.......................$1.29 + 0.99(2)
3 songs.......................$1.29 + 0.99(3)
4 songs.......................$1.29 + 0.99(4)
c songs.......................$1.29 + 0.99(c)
s(c) = 1.29 + 0.99c.
