Finding the Fourth Proportional to 9,911.88, 13,680.42 and 5,719.56

Step by Step Solution

1. Step 1: Write the proportion equation
   9,911.88 : 13,680.42 = 5,719.56 : x
2. Step 2: Convert to fraction form
   9,911.88/13,680.42 = 5,719.56/x
3. Step 3: Cross multiply
   9,911.88x = 13,680.42 × 5,719.56
4. Step 4: Simplify right side
   9,911.88x = 78,245,983.02
5. Step 5: Solve for x
   x = 78,245,983.02/9,911.88
6. Step 6: Final answer
   x = 7,894.16