Finding the Fourth Proportional to 1,443.38, 1,991.74 and 853.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.38 : 1,991.74 = 853.80 : x
2. Step 2: Convert to fraction form
   1,443.38/1,991.74 = 853.80/x
3. Step 3: Cross multiply
   1,443.38x = 1,991.74 × 853.80
4. Step 4: Simplify right side
   1,443.38x = 1,700,547.61
5. Step 5: Solve for x
   x = 1,700,547.61/1,443.38
6. Step 6: Final answer
   x = 1,178.17