Finding the Fourth Proportional to 1,399.81, 1,931.44 and 810.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.81 : 1,931.44 = 810.34 : x
2. Step 2: Convert to fraction form
   1,399.81/1,931.44 = 810.34/x
3. Step 3: Cross multiply
   1,399.81x = 1,931.44 × 810.34
4. Step 4: Simplify right side
   1,399.81x = 1,565,123.09
5. Step 5: Solve for x
   x = 1,565,123.09/1,399.81
6. Step 6: Final answer
   x = 1,118.10