Finding the Fourth Proportional to 9,913.12, 13,679.12 and 5,722.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,913.12 : 13,679.12 = 5,722.72 : x
2. Step 2: Convert to fraction form
   9,913.12/13,679.12 = 5,722.72/x
3. Step 3: Cross multiply
   9,913.12x = 13,679.12 × 5,722.72
4. Step 4: Simplify right side
   9,913.12x = 78,281,773.61
5. Step 5: Solve for x
   x = 78,281,773.61/9,913.12
6. Step 6: Final answer
   x = 7,896.78