Finding the Fourth Proportional to 1,109.88, 1,661.31 and 621.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.88 : 1,661.31 = 621.45 : x
2. Step 2: Convert to fraction form
   1,109.88/1,661.31 = 621.45/x
3. Step 3: Cross multiply
   1,109.88x = 1,661.31 × 621.45
4. Step 4: Simplify right side
   1,109.88x = 1,032,421.10
5. Step 5: Solve for x
   x = 1,032,421.10/1,109.88
6. Step 6: Final answer
   x = 930.21