Finding the Third Proportional to 311,580 and 488,149.50

Step by Step Solution

1. Step 1: Write the proportion equation
   311,580 : 488,149.50 = 488,149.50 : x
2. Step 2: Convert to fraction form
   311,580/488,149.50 = 488,149.50/x
3. Step 3: Cross multiply
   311,580x = 488,149.50 × 488,149.50
4. Step 4: Simplify right side
   311,580x = 238,289,934,350.25
5. Step 5: Solve for x
   x = 238,289,934,350.25/311,580
6. Step 6: Final answer
   x = 764,779.30