Finding the Fourth Proportional to 1,442.61, 1,991.12 and 918.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.61 : 1,991.12 = 918.81 : x
2. Step 2: Convert to fraction form
   1,442.61/1,991.12 = 918.81/x
3. Step 3: Cross multiply
   1,442.61x = 1,991.12 × 918.81
4. Step 4: Simplify right side
   1,442.61x = 1,829,456.37
5. Step 5: Solve for x
   x = 1,829,456.37/1,442.61
6. Step 6: Final answer
   x = 1,268.16