Finding the Fourth Proportional to 1,355.80, 1,869.72 and 935.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.80 : 1,869.72 = 935.48 : x
2. Step 2: Convert to fraction form
   1,355.80/1,869.72 = 935.48/x
3. Step 3: Cross multiply
   1,355.80x = 1,869.72 × 935.48
4. Step 4: Simplify right side
   1,355.80x = 1,749,085.67
5. Step 5: Solve for x
   x = 1,749,085.67/1,355.80
6. Step 6: Final answer
   x = 1,290.08