Finding the Fourth Proportional to 1,390.88, 1,919.64 and 801.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.88 : 1,919.64 = 801.32 : x
2. Step 2: Convert to fraction form
   1,390.88/1,919.64 = 801.32/x
3. Step 3: Cross multiply
   1,390.88x = 1,919.64 × 801.32
4. Step 4: Simplify right side
   1,390.88x = 1,538,236.33
5. Step 5: Solve for x
   x = 1,538,236.33/1,390.88
6. Step 6: Final answer
   x = 1,105.95