Finding the Fourth Proportional to 22,717, 31,353.60 and 21,720.70

Step by Step Solution

1. Step 1: Write the proportion equation
   22,717 : 31,353.60 = 21,720.70 : x
2. Step 2: Convert to fraction form
   22,717/31,353.60 = 21,720.70/x
3. Step 3: Cross multiply
   22,717x = 31,353.60 × 21,720.70
4. Step 4: Simplify right side
   22,717x = 681,022,139.52
5. Step 5: Solve for x
   x = 681,022,139.52/22,717
6. Step 6: Final answer
   x = 29,978.52