Finding the Fourth Proportional to 21,819.32, 30,109.22 and 12,866.40

Step by Step Solution

1. Step 1: Write the proportion equation
   21,819.32 : 30,109.22 = 12,866.40 : x
2. Step 2: Convert to fraction form
   21,819.32/30,109.22 = 12,866.40/x
3. Step 3: Cross multiply
   21,819.32x = 30,109.22 × 12,866.40
4. Step 4: Simplify right side
   21,819.32x = 387,397,268.21
5. Step 5: Solve for x
   x = 387,397,268.21/21,819.32
6. Step 6: Final answer
   x = 17,754.78