Finding the Third Proportional to 128,339.50 and 309,184.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,339.50 : 309,184.50 = 309,184.50 : x
2. Step 2: Convert to fraction form
   128,339.50/309,184.50 = 309,184.50/x
3. Step 3: Cross multiply
   128,339.50x = 309,184.50 × 309,184.50
4. Step 4: Simplify right side
   128,339.50x = 95,595,055,040.25
5. Step 5: Solve for x
   x = 95,595,055,040.25/128,339.50
6. Step 6: Final answer
   x = 744,860.74