Finding the Fourth Proportional to 1,390.99, 1,919.60 and 801.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.99 : 1,919.60 = 801.49 : x
2. Step 2: Convert to fraction form
   1,390.99/1,919.60 = 801.49/x
3. Step 3: Cross multiply
   1,390.99x = 1,919.60 × 801.49
4. Step 4: Simplify right side
   1,390.99x = 1,538,540.20
5. Step 5: Solve for x
   x = 1,538,540.20/1,390.99
6. Step 6: Final answer
   x = 1,106.08