This is the boss. No calculator — the readings are pinned so every line lands in your head. One sealed module, one long problem, and every answer feeds the next: the two meter readings give $R_{Th}$, the open-circuit reading is $V_{Th}$ for free, those two give $I_N$, and $V_{Th}$ with $R_{Th}$ gives the matched-load power. Write each line down as you go — one early slip rolls all the way to the last one.

Watch the two places this chapter takes its marks. The $-1$ in the Thevenin relation, which separates the module's own resistance from the whole loop. And the 4 in the matched-load power, which is the difference between a resistor and a smell.

Note what the last line actually asks. It does not want another number; it wants a DECISION about a part on the bench, the way a real check does. The arithmetic is only there to earn you the right to make it.

Everything in the chapter rides in this one box. 5★ under par here is the chapter crown. Clock in.