Finding the Fourth Proportional to 1,328.04, 1,990.86 and 558.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,328.04 : 1,990.86 = 558.12 : x
2. Step 2: Convert to fraction form
   1,328.04/1,990.86 = 558.12/x
3. Step 3: Cross multiply
   1,328.04x = 1,990.86 × 558.12
4. Step 4: Simplify right side
   1,328.04x = 1,111,138.78
5. Step 5: Solve for x
   x = 1,111,138.78/1,328.04
6. Step 6: Final answer
   x = 836.68