Finding the Third Proportional to 128,389.50 and 187,830

Step by Step Solution

1. Step 1: Write the proportion equation
   128,389.50 : 187,830 = 187,830 : x
2. Step 2: Convert to fraction form
   128,389.50/187,830 = 187,830/x
3. Step 3: Cross multiply
   128,389.50x = 187,830 × 187,830
4. Step 4: Simplify right side
   128,389.50x = 35,280,108,900
5. Step 5: Solve for x
   x = 35,280,108,900/128,389.50
6. Step 6: Final answer
   x = 274,789.67