Finding the Fourth Proportional to 1,390.55, 1,918.71 and 801.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.55 : 1,918.71 = 801.27 : x
2. Step 2: Convert to fraction form
   1,390.55/1,918.71 = 801.27/x
3. Step 3: Cross multiply
   1,390.55x = 1,918.71 × 801.27
4. Step 4: Simplify right side
   1,390.55x = 1,537,404.76
5. Step 5: Solve for x
   x = 1,537,404.76/1,390.55
6. Step 6: Final answer
   x = 1,105.61