Finding the Fourth Proportional to 8,919.91, 12,308.22 and 5,142.78

Step by Step Solution

1. Step 1: Write the proportion equation
   8,919.91 : 12,308.22 = 5,142.78 : x
2. Step 2: Convert to fraction form
   8,919.91/12,308.22 = 5,142.78/x
3. Step 3: Cross multiply
   8,919.91x = 12,308.22 × 5,142.78
4. Step 4: Simplify right side
   8,919.91x = 63,298,467.65
5. Step 5: Solve for x
   x = 63,298,467.65/8,919.91
6. Step 6: Final answer
   x = 7,096.31