1. The problem is to find the missing value in the proportion $43:14::54:x$. 2. By definition of proportion, the ratios are equal: $$\frac{43}{14} = \frac{54}{x}$$ 3. Cross-multiply to solve for $x$: $$43 \times x = 14 \times 54$$ 4. Calculate the right side: $$14 \times 54 = 756$$ 5. So, $$43x = 756$$ 6. Divide both sides by 43 to isolate $x$: $$x = \frac{756}{43}$$ 7. Simplify the fraction or calculate the decimal: $$x \approx 17.58$$ Final answer: $x = \frac{756}{43} \approx 17.58$