Rearranging Ohm’s Law

One formula, three answers. The Ohm’s Law triangle is a memory trick that hides all three rearrangements in a single picture. Put V on top, with I and R side by side below. Cover the quantity you want, and the layout shows you the formula:

• Cover V → the I and R sit side by side → V = I × R
• Cover I → V sits over R → I = V / R
• Cover R → V sits over I → R = V / I

This is the everyday workflow when designing a circuit: you usually know two of the three values and need the third. Sizing an LED resistor? You know the voltage to drop and the current you want, so you cover R and solve. It becomes second nature fast.