Finding the Fourth Proportional to 708,280, 977,426.42 and 390,328

Step by Step Solution

1. Step 1: Write the proportion equation
   708,280 : 977,426.42 = 390,328 : x
2. Step 2: Convert to fraction form
   708,280/977,426.42 = 390,328/x
3. Step 3: Cross multiply
   708,280x = 977,426.42 × 390,328
4. Step 4: Simplify right side
   708,280x = 381,516,899,665.76
5. Step 5: Solve for x
   x = 381,516,899,665.76/708,280
6. Step 6: Final answer
   x = 538,652.65