Finding the Fourth Proportional to 3,915.57, 5,873.57 and 993.90

Step by Step Solution

1. Step 1: Write the proportion equation
   3,915.57 : 5,873.57 = 993.90 : x
2. Step 2: Convert to fraction form
   3,915.57/5,873.57 = 993.90/x
3. Step 3: Cross multiply
   3,915.57x = 5,873.57 × 993.90
4. Step 4: Simplify right side
   3,915.57x = 5,837,741.22
5. Step 5: Solve for x
   x = 5,837,741.22/3,915.57
6. Step 6: Final answer
   x = 1,490.90