Finding the Fourth Proportional to 21,815, 30,104.76 and 12,385.04

Step by Step Solution

1. Step 1: Write the proportion equation
   21,815 : 30,104.76 = 12,385.04 : x
2. Step 2: Convert to fraction form
   21,815/30,104.76 = 12,385.04/x
3. Step 3: Cross multiply
   21,815x = 30,104.76 × 12,385.04
4. Step 4: Simplify right side
   21,815x = 372,848,656.79
5. Step 5: Solve for x
   x = 372,848,656.79/21,815
6. Step 6: Final answer
   x = 17,091.39