Finding the Fourth Proportional to 21,061.80, 31,610.88 and 8,588.70

Step by Step Solution

1. Step 1: Write the proportion equation
   21,061.80 : 31,610.88 = 8,588.70 : x
2. Step 2: Convert to fraction form
   21,061.80/31,610.88 = 8,588.70/x
3. Step 3: Cross multiply
   21,061.80x = 31,610.88 × 8,588.70
4. Step 4: Simplify right side
   21,061.80x = 271,496,365.06
5. Step 5: Solve for x
   x = 271,496,365.06/21,061.80
6. Step 6: Final answer
   x = 12,890.46