Finding the Fourth Proportional to 938.76, 1,406.89 and 721.27

Step by Step Solution

1. Step 1: Write the proportion equation
   938.76 : 1,406.89 = 721.27 : x
2. Step 2: Convert to fraction form
   938.76/1,406.89 = 721.27/x
3. Step 3: Cross multiply
   938.76x = 1,406.89 × 721.27
4. Step 4: Simplify right side
   938.76x = 1,014,747.55
5. Step 5: Solve for x
   x = 1,014,747.55/938.76
6. Step 6: Final answer
   x = 1,080.94