Finding the Fourth Proportional to 21,128.50, 31,703.69 and 10,740.25

Step by Step Solution

1. Step 1: Write the proportion equation
   21,128.50 : 31,703.69 = 10,740.25 : x
2. Step 2: Convert to fraction form
   21,128.50/31,703.69 = 10,740.25/x
3. Step 3: Cross multiply
   21,128.50x = 31,703.69 × 10,740.25
4. Step 4: Simplify right side
   21,128.50x = 340,505,556.52
5. Step 5: Solve for x
   x = 340,505,556.52/21,128.50
6. Step 6: Final answer
   x = 16,115.94