12. The value of the 4th term is 80. The sequence is being doubled at each step.
Explicit equation: y = 5(24)
Recursive:: now = previous term * 2
Find the value of the 7th term.
Explanation:

both equations and proportions are better.

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.