Finding the Fourth Proportional to 1,399.70, 1,931.56 and 810.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.70 : 1,931.56 = 810.22 : x
2. Step 2: Convert to fraction form
   1,399.70/1,931.56 = 810.22/x
3. Step 3: Cross multiply
   1,399.70x = 1,931.56 × 810.22
4. Step 4: Simplify right side
   1,399.70x = 1,564,988.54
5. Step 5: Solve for x
   x = 1,564,988.54/1,399.70
6. Step 6: Final answer
   x = 1,118.09