Finding the Fourth Proportional to 1,443.18, 1,991.76 and 853.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.18 : 1,991.76 = 853.92 : x
2. Step 2: Convert to fraction form
   1,443.18/1,991.76 = 853.92/x
3. Step 3: Cross multiply
   1,443.18x = 1,991.76 × 853.92
4. Step 4: Simplify right side
   1,443.18x = 1,700,803.70
5. Step 5: Solve for x
   x = 1,700,803.70/1,443.18
6. Step 6: Final answer
   x = 1,178.51