Finding the Third Proportional to 398,658 and 599,139

Step by Step Solution

1. Step 1: Write the proportion equation
   398,658 : 599,139 = 599,139 : x
2. Step 2: Convert to fraction form
   398,658/599,139 = 599,139/x
3. Step 3: Cross multiply
   398,658x = 599,139 × 599,139
4. Step 4: Simplify right side
   398,658x = 358,967,541,321
5. Step 5: Solve for x
   x = 358,967,541,321/398,658
6. Step 6: Final answer
   x = 900,439.83