Finding the Fourth Proportional to 21,816.12, 30,113.46 and 12,866.16

Step by Step Solution

1. Step 1: Write the proportion equation
   21,816.12 : 30,113.46 = 12,866.16 : x
2. Step 2: Convert to fraction form
   21,816.12/30,113.46 = 12,866.16/x
3. Step 3: Cross multiply
   21,816.12x = 30,113.46 × 12,866.16
4. Step 4: Simplify right side
   21,816.12x = 387,444,594.51
5. Step 5: Solve for x
   x = 387,444,594.51/21,816.12
6. Step 6: Final answer
   x = 17,759.56