Finding the Fourth Proportional to 1,399.73, 1,931.50 and 810.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.73 : 1,931.50 = 810.30 : x
2. Step 2: Convert to fraction form
   1,399.73/1,931.50 = 810.30/x
3. Step 3: Cross multiply
   1,399.73x = 1,931.50 × 810.30
4. Step 4: Simplify right side
   1,399.73x = 1,565,090.40
5. Step 5: Solve for x
   x = 1,565,090.40/1,399.73
6. Step 6: Final answer
   x = 1,118.14