Finding the Fourth Proportional to 3,972.12, 5,478.96 and 3,131.52

Step by Step Solution

1. Step 1: Write the proportion equation
   3,972.12 : 5,478.96 = 3,131.52 : x
2. Step 2: Convert to fraction form
   3,972.12/5,478.96 = 3,131.52/x
3. Step 3: Cross multiply
   3,972.12x = 5,478.96 × 3,131.52
4. Step 4: Simplify right side
   3,972.12x = 17,157,472.82
5. Step 5: Solve for x
   x = 17,157,472.82/3,972.12
6. Step 6: Final answer
   x = 4,319.47