Finding the Fourth Proportional to 1,440.86, 1,988.45 and 811.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,440.86 : 1,988.45 = 811.38 : x
2. Step 2: Convert to fraction form
   1,440.86/1,988.45 = 811.38/x
3. Step 3: Cross multiply
   1,440.86x = 1,988.45 × 811.38
4. Step 4: Simplify right side
   1,440.86x = 1,613,384.50
5. Step 5: Solve for x
   x = 1,613,384.50/1,440.86
6. Step 6: Final answer
   x = 1,119.74