Finding the Fourth Proportional to 1,443.11, 1,991.72 and 853.97

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.11 : 1,991.72 = 853.97 : x
2. Step 2: Convert to fraction form
   1,443.11/1,991.72 = 853.97/x
3. Step 3: Cross multiply
   1,443.11x = 1,991.72 × 853.97
4. Step 4: Simplify right side
   1,443.11x = 1,700,861.30
5. Step 5: Solve for x
   x = 1,700,861.30/1,443.11
6. Step 6: Final answer
   x = 1,178.61