Finding the Fourth Proportional to 21,819.28, 32,731.48 and 7,781.30

Step by Step Solution

1. Step 1: Write the proportion equation
   21,819.28 : 32,731.48 = 7,781.30 : x
2. Step 2: Convert to fraction form
   21,819.28/32,731.48 = 7,781.30/x
3. Step 3: Cross multiply
   21,819.28x = 32,731.48 × 7,781.30
4. Step 4: Simplify right side
   21,819.28x = 254,693,406.78
5. Step 5: Solve for x
   x = 254,693,406.78/21,819.28
6. Step 6: Final answer
   x = 11,672.86