Finding the Third Proportional to 90,643.50 and 198,418.50

Step by Step Solution

1. Step 1: Write the proportion equation
   90,643.50 : 198,418.50 = 198,418.50 : x
2. Step 2: Convert to fraction form
   90,643.50/198,418.50 = 198,418.50/x
3. Step 3: Cross multiply
   90,643.50x = 198,418.50 × 198,418.50
4. Step 4: Simplify right side
   90,643.50x = 39,369,901,142.25
5. Step 5: Solve for x
   x = 39,369,901,142.25/90,643.50
6. Step 6: Final answer
   x = 434,337.83