Finding the Fourth Proportional to 1,359.20, 1,873.92 and 980.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,359.20 : 1,873.92 = 980.78 : x
2. Step 2: Convert to fraction form
   1,359.20/1,873.92 = 980.78/x
3. Step 3: Cross multiply
   1,359.20x = 1,873.92 × 980.78
4. Step 4: Simplify right side
   1,359.20x = 1,837,892.55
5. Step 5: Solve for x
   x = 1,837,892.55/1,359.20
6. Step 6: Final answer
   x = 1,352.18