Finding the Fourth Proportional to 10,931.42, 16,399.56 and 3,139.64

Step by Step Solution

1. Step 1: Write the proportion equation
   10,931.42 : 16,399.56 = 3,139.64 : x
2. Step 2: Convert to fraction form
   10,931.42/16,399.56 = 3,139.64/x
3. Step 3: Cross multiply
   10,931.42x = 16,399.56 × 3,139.64
4. Step 4: Simplify right side
   10,931.42x = 51,488,714.56
5. Step 5: Solve for x
   x = 51,488,714.56/10,931.42
6. Step 6: Final answer
   x = 4,710.16