Finding the Fourth Proportional to 21,003.19, 31,462.71 and 12,657.96

Step by Step Solution

1. Step 1: Write the proportion equation
   21,003.19 : 31,462.71 = 12,657.96 : x
2. Step 2: Convert to fraction form
   21,003.19/31,462.71 = 12,657.96/x
3. Step 3: Cross multiply
   21,003.19x = 31,462.71 × 12,657.96
4. Step 4: Simplify right side
   21,003.19x = 398,253,724.67
5. Step 5: Solve for x
   x = 398,253,724.67/21,003.19
6. Step 6: Final answer
   x = 18,961.58