Finding the Third Proportional to 399,091.50 and 861,484.50

Step by Step Solution

1. Step 1: Write the proportion equation
   399,091.50 : 861,484.50 = 861,484.50 : x
2. Step 2: Convert to fraction form
   399,091.50/861,484.50 = 861,484.50/x
3. Step 3: Cross multiply
   399,091.50x = 861,484.50 × 861,484.50
4. Step 4: Simplify right side
   399,091.50x = 742,155,543,740.25
5. Step 5: Solve for x
   x = 742,155,543,740.25/399,091.50
6. Step 6: Final answer
   x = 1,859,612.50