Finding the Fourth Proportional to 1,390.54, 1,919.32 and 801.17

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.54 : 1,919.32 = 801.17 : x
2. Step 2: Convert to fraction form
   1,390.54/1,919.32 = 801.17/x
3. Step 3: Cross multiply
   1,390.54x = 1,919.32 × 801.17
4. Step 4: Simplify right side
   1,390.54x = 1,537,701.60
5. Step 5: Solve for x
   x = 1,537,701.60/1,390.54
6. Step 6: Final answer
   x = 1,105.83