Finding the Fourth Proportional to 1,443.16, 1,991.58 and 853.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.16 : 1,991.58 = 853.68 : x
2. Step 2: Convert to fraction form
   1,443.16/1,991.58 = 853.68/x
3. Step 3: Cross multiply
   1,443.16x = 1,991.58 × 853.68
4. Step 4: Simplify right side
   1,443.16x = 1,700,172.01
5. Step 5: Solve for x
   x = 1,700,172.01/1,443.16
6. Step 6: Final answer
   x = 1,178.09