Finding the Fourth Proportional to 1,288.46, 1,778.10 and 764.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.46 : 1,778.10 = 764.48 : x
2. Step 2: Convert to fraction form
   1,288.46/1,778.10 = 764.48/x
3. Step 3: Cross multiply
   1,288.46x = 1,778.10 × 764.48
4. Step 4: Simplify right side
   1,288.46x = 1,359,321.89
5. Step 5: Solve for x
   x = 1,359,321.89/1,288.46
6. Step 6: Final answer
   x = 1,055.00