1. Stating the problem: We need to find the principal amount given the interest earned, rate, and time. 2. Formula for simple interest: $$I = P \times r \times t$$ where $I$ is interest, $P$ is principal, $r$ is rate (in decimal), and $t$ is time in years. 3. Given: $I = 7200$, $r = 6\% = 0.06$, $t = 4$ years. 4. Substitute the values into the formula: $$7200 = P \times 0.06 \times 4$$ 5. Simplify the right side: $$7200 = P \times 0.24$$ 6. To isolate $P$, divide both sides by $0.24$: $$P = \frac{7200}{0.24}$$ 7. Show cancellation: $$P = \frac{7200}{\cancel{0.24}} \times \frac{1}{\cancel{1}}$$ 8. Calculate $P$: $$P = 30000$$ Final answer: The principal is 30000.