Finding the Fourth Proportional to 9,920.86, 13,690.71 and 5,731.42

Step by Step Solution

1. Step 1: Write the proportion equation
   9,920.86 : 13,690.71 = 5,731.42 : x
2. Step 2: Convert to fraction form
   9,920.86/13,690.71 = 5,731.42/x
3. Step 3: Cross multiply
   9,920.86x = 13,690.71 × 5,731.42
4. Step 4: Simplify right side
   9,920.86x = 78,467,209.11
5. Step 5: Solve for x
   x = 78,467,209.11/9,920.86
6. Step 6: Final answer
   x = 7,909.32