This is a geometric sequence with common ratio (r) = 2.
an = ar^(n - 1)
a4 = a(2)^(4 - 1) = a(2)^3 = 8a
8a = 80
a = 80/8 = 10
7th term (a7) = 10(2)^(7 - 1) = 10(2^6) = 10(64) = 640
64 feet squared because 4 cubes
Answer:
x = 10
Step-by-step explanation:
By looking at the picture, I can tell the angle of the 3x is also 30 degrees.
This means 3x = 30.
When you solve for x by dividing each side by 3, you result with the answer of x = 10.
To check you work, plug in 10 for x to recieve 30 degrees again.