Finding the Fourth Proportional to 1,390.71, 1,919.18 and 801.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.71 : 1,919.18 = 801.24 : x
2. Step 2: Convert to fraction form
   1,390.71/1,919.18 = 801.24/x
3. Step 3: Cross multiply
   1,390.71x = 1,919.18 × 801.24
4. Step 4: Simplify right side
   1,390.71x = 1,537,719.78
5. Step 5: Solve for x
   x = 1,537,719.78/1,390.71
6. Step 6: Final answer
   x = 1,105.71