Finding the Fourth Proportional to 21,771.72, 32,672.13 and 7,920.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,771.72 : 32,672.13 = 7,920.72 : x
2. Step 2: Convert to fraction form
   21,771.72/32,672.13 = 7,920.72/x
3. Step 3: Cross multiply
   21,771.72x = 32,672.13 × 7,920.72
4. Step 4: Simplify right side
   21,771.72x = 258,786,793.53
5. Step 5: Solve for x
   x = 258,786,793.53/21,771.72
6. Step 6: Final answer
   x = 11,886.37