Finding the Fourth Proportional to 1,399.24, 1,931.19 and 810.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.24 : 1,931.19 = 810.12 : x
2. Step 2: Convert to fraction form
   1,399.24/1,931.19 = 810.12/x
3. Step 3: Cross multiply
   1,399.24x = 1,931.19 × 810.12
4. Step 4: Simplify right side
   1,399.24x = 1,564,495.64
5. Step 5: Solve for x
   x = 1,564,495.64/1,399.24
6. Step 6: Final answer
   x = 1,118.10