Finding the Fourth Proportional to 1,111.07, 1,662.93 and 989.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.07 : 1,662.93 = 989.57 : x
2. Step 2: Convert to fraction form
   1,111.07/1,662.93 = 989.57/x
3. Step 3: Cross multiply
   1,111.07x = 1,662.93 × 989.57
4. Step 4: Simplify right side
   1,111.07x = 1,645,585.64
5. Step 5: Solve for x
   x = 1,645,585.64/1,111.07
6. Step 6: Final answer
   x = 1,481.08