Finding the Third Proportional to 249,123 and 391,540.50

Step by Step Solution

1. Step 1: Write the proportion equation
   249,123 : 391,540.50 = 391,540.50 : x
2. Step 2: Convert to fraction form
   249,123/391,540.50 = 391,540.50/x
3. Step 3: Cross multiply
   249,123x = 391,540.50 × 391,540.50
4. Step 4: Simplify right side
   249,123x = 153,303,963,140.25
5. Step 5: Solve for x
   x = 153,303,963,140.25/249,123
6. Step 6: Final answer
   x = 615,374.59