F(4)=1
If g(x) = 2, x=

f\left(x\right)=\frac{1}{x^2}

Step-by-step explanation:

i believe the answer is the polygon, heptagon.

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.