Finding the Fourth Proportional to 1,442.16, 1,991.52 and 917.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.16 : 1,991.52 = 917.28 : x
2. Step 2: Convert to fraction form
   1,442.16/1,991.52 = 917.28/x
3. Step 3: Cross multiply
   1,442.16x = 1,991.52 × 917.28
4. Step 4: Simplify right side
   1,442.16x = 1,826,781.47
5. Step 5: Solve for x
   x = 1,826,781.47/1,442.16
6. Step 6: Final answer
   x = 1,266.70