Finding the Third Proportional to 257,991 and 398,488.50

Step by Step Solution

1. Step 1: Write the proportion equation
   257,991 : 398,488.50 = 398,488.50 : x
2. Step 2: Convert to fraction form
   257,991/398,488.50 = 398,488.50/x
3. Step 3: Cross multiply
   257,991x = 398,488.50 × 398,488.50
4. Step 4: Simplify right side
   257,991x = 158,793,084,632.25
5. Step 5: Solve for x
   x = 158,793,084,632.25/257,991
6. Step 6: Final answer
   x = 615,498.54