Finding the Third Proportional to 258,655.50 and 399,054

Step by Step Solution

1. Step 1: Write the proportion equation
   258,655.50 : 399,054 = 399,054 : x
2. Step 2: Convert to fraction form
   258,655.50/399,054 = 399,054/x
3. Step 3: Cross multiply
   258,655.50x = 399,054 × 399,054
4. Step 4: Simplify right side
   258,655.50x = 159,244,094,916
5. Step 5: Solve for x
   x = 159,244,094,916/258,655.50
6. Step 6: Final answer
   x = 615,660.97