Finding the Fourth Proportional to 9,919.56, 13,688.88 and 5,727.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,919.56 : 13,688.88 = 5,727.72 : x
2. Step 2: Convert to fraction form
   9,919.56/13,688.88 = 5,727.72/x
3. Step 3: Cross multiply
   9,919.56x = 13,688.88 × 5,727.72
4. Step 4: Simplify right side
   9,919.56x = 78,406,071.75
5. Step 5: Solve for x
   x = 78,406,071.75/9,919.56
6. Step 6: Final answer
   x = 7,904.19