Finding the Fourth Proportional to 1,399.67, 1,931.60 and 770.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.67 : 1,931.60 = 770.23 : x
2. Step 2: Convert to fraction form
   1,399.67/1,931.60 = 770.23/x
3. Step 3: Cross multiply
   1,399.67x = 1,931.60 × 770.23
4. Step 4: Simplify right side
   1,399.67x = 1,487,776.27
5. Step 5: Solve for x
   x = 1,487,776.27/1,399.67
6. Step 6: Final answer
   x = 1,062.95