Finding the Third Proportional to 128,643 and 198,796.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,643 : 198,796.50 = 198,796.50 : x
2. Step 2: Convert to fraction form
   128,643/198,796.50 = 198,796.50/x
3. Step 3: Cross multiply
   128,643x = 198,796.50 × 198,796.50
4. Step 4: Simplify right side
   128,643x = 39,520,048,412.25
5. Step 5: Solve for x
   x = 39,520,048,412.25/128,643
6. Step 6: Final answer
   x = 307,207.14