Finding the Fourth Proportional to 1,399.76, 1,931.72 and 810.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.76 : 1,931.72 = 810.36 : x
2. Step 2: Convert to fraction form
   1,399.76/1,931.72 = 810.36/x
3. Step 3: Cross multiply
   1,399.76x = 1,931.72 × 810.36
4. Step 4: Simplify right side
   1,399.76x = 1,565,388.62
5. Step 5: Solve for x
   x = 1,565,388.62/1,399.76
6. Step 6: Final answer
   x = 1,118.33