Finding the Fourth Proportional to 1,390.62, 1,919.25 and 801.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.62 : 1,919.25 = 801.15 : x
2. Step 2: Convert to fraction form
   1,390.62/1,919.25 = 801.15/x
3. Step 3: Cross multiply
   1,390.62x = 1,919.25 × 801.15
4. Step 4: Simplify right side
   1,390.62x = 1,537,607.14
5. Step 5: Solve for x
   x = 1,537,607.14/1,390.62
6. Step 6: Final answer
   x = 1,105.70