To find the resistance of the unknown component, we can use Ohm's law (V = IR). Given that the total voltage (V) is 90 volts and the current (I) is 2.25 amps, we can calculate the total resistance (R) using the formula R = V/I.
So, R = 90 / 2.25 = 40 Ω.
Next, we know the total resistance of the circuit is (5x + 20) Ω, so we set it equal to the calculated resistance:
5x + 20 = 40.
Solving for x, we get 5x = 20, thus x = 4 Ω.
The resistance of the unknown component is 4 Ω.