Finding the Fourth Proportional to 1,399.62, 1,931.52 and 770.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.62 : 1,931.52 = 770.16 : x
2. Step 2: Convert to fraction form
   1,399.62/1,931.52 = 770.16/x
3. Step 3: Cross multiply
   1,399.62x = 1,931.52 × 770.16
4. Step 4: Simplify right side
   1,399.62x = 1,487,579.44
5. Step 5: Solve for x
   x = 1,487,579.44/1,399.62
6. Step 6: Final answer
   x = 1,062.85