Finding the Fourth Proportional to 2,385.96, 3,578.80 and 998.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,385.96 : 3,578.80 = 998.57 : x
2. Step 2: Convert to fraction form
   2,385.96/3,578.80 = 998.57/x
3. Step 3: Cross multiply
   2,385.96x = 3,578.80 × 998.57
4. Step 4: Simplify right side
   2,385.96x = 3,573,659.43
5. Step 5: Solve for x
   x = 3,573,659.43/2,385.96
6. Step 6: Final answer
   x = 1,497.79