Finding the Fourth Proportional to 1,399.65, 1,931.46 and 770.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.65 : 1,931.46 = 770.18 : x
2. Step 2: Convert to fraction form
   1,399.65/1,931.46 = 770.18/x
3. Step 3: Cross multiply
   1,399.65x = 1,931.46 × 770.18
4. Step 4: Simplify right side
   1,399.65x = 1,487,562.21
5. Step 5: Solve for x
   x = 1,487,562.21/1,399.65
6. Step 6: Final answer
   x = 1,062.81