Finding the Fourth Proportional to 10,380.42, 15,557.67 and 5,187.78

Step by Step Solution

1. Step 1: Write the proportion equation
   10,380.42 : 15,557.67 = 5,187.78 : x
2. Step 2: Convert to fraction form
   10,380.42/15,557.67 = 5,187.78/x
3. Step 3: Cross multiply
   10,380.42x = 15,557.67 × 5,187.78
4. Step 4: Simplify right side
   10,380.42x = 80,709,769.27
5. Step 5: Solve for x
   x = 80,709,769.27/10,380.42
6. Step 6: Final answer
   x = 7,775.19