Question

three resistors if 8 ohm are connected to a triangle thr resistance between any 2 terminals

Answer 1

R1, R2 & R3 are each 8 Ohms and the terminals are labeled N1, N2 & N3. No matter which two terminals you measure from, you always end up with one resistor in parallel with two resistors in series. So if you solve Rt for two terminals, you'll solve Rt for any two terminals because the resistors are the same value.

For resistors in series, you add: 8 + 8 = 16 Ohms.

Now use the equation for parallel resistors: 1/Rt = 1/16 + 1/8

Solve for Rt and you'll have your answer for resistance at any two terminals.