Finding the Fourth Proportional to 1,440.91, 1,988.39 and 811.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,440.91 : 1,988.39 = 811.47 : x
2. Step 2: Convert to fraction form
   1,440.91/1,988.39 = 811.47/x
3. Step 3: Cross multiply
   1,440.91x = 1,988.39 × 811.47
4. Step 4: Simplify right side
   1,440.91x = 1,613,520.86
5. Step 5: Solve for x
   x = 1,613,520.86/1,440.91
6. Step 6: Final answer
   x = 1,119.79