Finding the Fourth Proportional to 1,111.78, 1,533.49 and 718.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.78 : 1,533.49 = 718.71 : x
2. Step 2: Convert to fraction form
   1,111.78/1,533.49 = 718.71/x
3. Step 3: Cross multiply
   1,111.78x = 1,533.49 × 718.71
4. Step 4: Simplify right side
   1,111.78x = 1,102,134.60
5. Step 5: Solve for x
   x = 1,102,134.60/1,111.78
6. Step 6: Final answer
   x = 991.32