Finding the Fourth Proportional to 6,641.70, 9,955.38 and 3,128.76

Step by Step Solution

1. Step 1: Write the proportion equation
   6,641.70 : 9,955.38 = 3,128.76 : x
2. Step 2: Convert to fraction form
   6,641.70/9,955.38 = 3,128.76/x
3. Step 3: Cross multiply
   6,641.70x = 9,955.38 × 3,128.76
4. Step 4: Simplify right side
   6,641.70x = 31,147,994.73
5. Step 5: Solve for x
   x = 31,147,994.73/6,641.70
6. Step 6: Final answer
   x = 4,689.76