Finding the Fourth Proportional to 21,158.70, 31,719.42 and 8,020.32

Step by Step Solution

1. Step 1: Write the proportion equation
   21,158.70 : 31,719.42 = 8,020.32 : x
2. Step 2: Convert to fraction form
   21,158.70/31,719.42 = 8,020.32/x
3. Step 3: Cross multiply
   21,158.70x = 31,719.42 × 8,020.32
4. Step 4: Simplify right side
   21,158.70x = 254,399,898.61
5. Step 5: Solve for x
   x = 254,399,898.61/21,158.70
6. Step 6: Final answer
   x = 12,023.42