Finding the Fourth Proportional to 21,742.88, 30,002.24 and 12,785.20

Step by Step Solution

1. Step 1: Write the proportion equation
   21,742.88 : 30,002.24 = 12,785.20 : x
2. Step 2: Convert to fraction form
   21,742.88/30,002.24 = 12,785.20/x
3. Step 3: Cross multiply
   21,742.88x = 30,002.24 × 12,785.20
4. Step 4: Simplify right side
   21,742.88x = 383,584,638.85
5. Step 5: Solve for x
   x = 383,584,638.85/21,742.88
6. Step 6: Final answer
   x = 17,641.85