Finding the Fourth Proportional to 1,180.88, 1,771.55 and 661.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,180.88 : 1,771.55 = 661.61 : x
2. Step 2: Convert to fraction form
   1,180.88/1,771.55 = 661.61/x
3. Step 3: Cross multiply
   1,180.88x = 1,771.55 × 661.61
4. Step 4: Simplify right side
   1,180.88x = 1,172,076.32
5. Step 5: Solve for x
   x = 1,172,076.32/1,180.88
6. Step 6: Final answer
   x = 992.55