1. **State the problem:** We need to find the number $x$ such that 81 is 78% of $x$. 2. **Write the equation:** Since 78% means $\frac{78}{100}$, the equation is: $$81 = \frac{78}{100} \times x$$ 3. **Solve for $x$:** $$x = \frac{81}{\frac{78}{100}}$$ 4. **Simplify the division:** $$x = 81 \times \frac{100}{78}$$ 5. **Calculate the value:** $$x = \frac{81 \times 100}{78} = \frac{8100}{78}$$ 6. **Simplify the fraction:** $$x = \frac{\cancel{6} \times 1350}{\cancel{6} \times 13} = \frac{1350}{13} \approx 103.85$$ **Final answer:** $$x \approx 103.85$$ So, 81 is 78% of approximately 103.85.