Finding the Fourth Proportional to 1,399.55, 1,931.54 and 810.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.55 : 1,931.54 = 810.07 : x
2. Step 2: Convert to fraction form
   1,399.55/1,931.54 = 810.07/x
3. Step 3: Cross multiply
   1,399.55x = 1,931.54 × 810.07
4. Step 4: Simplify right side
   1,399.55x = 1,564,673.73
5. Step 5: Solve for x
   x = 1,564,673.73/1,399.55
6. Step 6: Final answer
   x = 1,117.99