Finding the Fourth Proportional to 2,635.61, 3,951.34 and 991.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,635.61 : 3,951.34 = 991.96 : x
2. Step 2: Convert to fraction form
   2,635.61/3,951.34 = 991.96/x
3. Step 3: Cross multiply
   2,635.61x = 3,951.34 × 991.96
4. Step 4: Simplify right side
   2,635.61x = 3,919,558.87
5. Step 5: Solve for x
   x = 3,919,558.87/2,635.61
6. Step 6: Final answer
   x = 1,487.16