Finding the Fourth Proportional to 1,443.25, 1,991.61 and 853.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.25 : 1,991.61 = 853.98 : x
2. Step 2: Convert to fraction form
   1,443.25/1,991.61 = 853.98/x
3. Step 3: Cross multiply
   1,443.25x = 1,991.61 × 853.98
4. Step 4: Simplify right side
   1,443.25x = 1,700,795.11
5. Step 5: Solve for x
   x = 1,700,795.11/1,443.25
6. Step 6: Final answer
   x = 1,178.45