Finding the Third Proportional to 128,789.16 and 279,745.31

Step by Step Solution

1. Step 1: Write the proportion equation
   128,789.16 : 279,745.31 = 279,745.31 : x
2. Step 2: Convert to fraction form
   128,789.16/279,745.31 = 279,745.31/x
3. Step 3: Cross multiply
   128,789.16x = 279,745.31 × 279,745.31
4. Step 4: Simplify right side
   128,789.16x = 78,257,439,865.72
5. Step 5: Solve for x
   x = 78,257,439,865.72/128,789.16
6. Step 6: Final answer
   x = 607,639.98