Finding the Fourth Proportional to 1,442.88, 1,991.06 and 853.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.88 : 1,991.06 = 853.30 : x
2. Step 2: Convert to fraction form
   1,442.88/1,991.06 = 853.30/x
3. Step 3: Cross multiply
   1,442.88x = 1,991.06 × 853.30
4. Step 4: Simplify right side
   1,442.88x = 1,698,971.50
5. Step 5: Solve for x
   x = 1,698,971.50/1,442.88
6. Step 6: Final answer
   x = 1,177.49