Finding the Fourth Proportional to 1,443.37, 1,991.73 and 853.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.37 : 1,991.73 = 853.78 : x
2. Step 2: Convert to fraction form
   1,443.37/1,991.73 = 853.78/x
3. Step 3: Cross multiply
   1,443.37x = 1,991.73 × 853.78
4. Step 4: Simplify right side
   1,443.37x = 1,700,499.24
5. Step 5: Solve for x
   x = 1,700,499.24/1,443.37
6. Step 6: Final answer
   x = 1,178.15