Finding the Third Proportional to 128,938.50 and 284,040

Step by Step Solution

1. Step 1: Write the proportion equation
   128,938.50 : 284,040 = 284,040 : x
2. Step 2: Convert to fraction form
   128,938.50/284,040 = 284,040/x
3. Step 3: Cross multiply
   128,938.50x = 284,040 × 284,040
4. Step 4: Simplify right side
   128,938.50x = 80,678,721,600
5. Step 5: Solve for x
   x = 80,678,721,600/128,938.50
6. Step 6: Final answer
   x = 625,714.75