Finding the Fourth Proportional to 1,443.29, 1,991.63 and 853.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.29 : 1,991.63 = 853.61 : x
2. Step 2: Convert to fraction form
   1,443.29/1,991.63 = 853.61/x
3. Step 3: Cross multiply
   1,443.29x = 1,991.63 × 853.61
4. Step 4: Simplify right side
   1,443.29x = 1,700,061.06
5. Step 5: Solve for x
   x = 1,700,061.06/1,443.29
6. Step 6: Final answer
   x = 1,177.91