Finding the Third Proportional to 390,346 and 582,280.50

Step by Step Solution

1. Step 1: Write the proportion equation
   390,346 : 582,280.50 = 582,280.50 : x
2. Step 2: Convert to fraction form
   390,346/582,280.50 = 582,280.50/x
3. Step 3: Cross multiply
   390,346x = 582,280.50 × 582,280.50
4. Step 4: Simplify right side
   390,346x = 339,050,580,680.25
5. Step 5: Solve for x
   x = 339,050,580,680.25/390,346
6. Step 6: Final answer
   x = 868,589.87