Finding the Fourth Proportional to 8,990.31, 12,406.74 and 5,162.55

Step by Step Solution

1. Step 1: Write the proportion equation
   8,990.31 : 12,406.74 = 5,162.55 : x
2. Step 2: Convert to fraction form
   8,990.31/12,406.74 = 5,162.55/x
3. Step 3: Cross multiply
   8,990.31x = 12,406.74 × 5,162.55
4. Step 4: Simplify right side
   8,990.31x = 64,050,415.59
5. Step 5: Solve for x
   x = 64,050,415.59/8,990.31
6. Step 6: Final answer
   x = 7,124.38