On the path between the two X's, R11 is in parallel with everything else. The other branch is R8 in series with the R9-R10 combination.

The R9-R10 combination has a resistance of 2250 ohms.

The R8-R9-R10 combo has a resistance of 6750 ohms.

Then the R8-R9-R10-R11 combo has a resistance of

1 / [1/4500 + 1/6750] = 2700 ohms.

R9>>R10>>>>>R8>>>>>>>> R11



4500/2= 2250+4500=6750>>(4500*6750)/(4500+6750)= 2700 Ω

1/ R = 1 / 4500 + 1 / 6750

solve R , answer in ohm

Rt = [(4500 || 4500) + 4500] || 4500 = [(2250 + 4500) || 4500] = [6750 || 4500] = 2,700 Ohms