Finding the Fourth Proportional to 1,443.26, 1,991.80 and 813.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.26 : 1,991.80 = 813.86 : x
2. Step 2: Convert to fraction form
   1,443.26/1,991.80 = 813.86/x
3. Step 3: Cross multiply
   1,443.26x = 1,991.80 × 813.86
4. Step 4: Simplify right side
   1,443.26x = 1,621,034.35
5. Step 5: Solve for x
   x = 1,621,034.35/1,443.26
6. Step 6: Final answer
   x = 1,123.18