Answer:
495
Step-by-step explanation:
In order to find the sum of the first 18 terms you have to find the 18th term and the first term using the equation given.
a1=3(1)-1 a1=2
a18=3(18)-1 a18= 53
Then plug in 53 for an, 18 for n, and 2 in for a1 in the sum equation: Sn=n/2(a1+an)
Sn=18/2(2+53) Solve for sn= 495
Answer:
5
Step-by-step explanation:
There are 5 faces on a square pyramid
If it is parallel lines cut by a transversal then they are probably equal. Alternate exterior.
The fourth term in the arithmetic sequence is 4. This is because you are subtracting 3 each time, and you already have your first three numbers in the pattern, so all you have to do is subtract another 3 in order to get 4.
Cross multiply:
2.5 ft x 16.5 ft = 41.25 ft
now divide:
41.25 / 8.25 = 5
L = 5 feet
