Finding the Third Proportional to 399,285 and 603,085.50

Step by Step Solution

1. Step 1: Write the proportion equation
   399,285 : 603,085.50 = 603,085.50 : x
2. Step 2: Convert to fraction form
   399,285/603,085.50 = 603,085.50/x
3. Step 3: Cross multiply
   399,285x = 603,085.50 × 603,085.50
4. Step 4: Simplify right side
   399,285x = 363,712,120,310.25
5. Step 5: Solve for x
   x = 363,712,120,310.25/399,285
6. Step 6: Final answer
   x = 910,908.55