Finding the Fourth Proportional to 1,320.68, 1,978.18 and 772.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.68 : 1,978.18 = 772.32 : x
2. Step 2: Convert to fraction form
   1,320.68/1,978.18 = 772.32/x
3. Step 3: Cross multiply
   1,320.68x = 1,978.18 × 772.32
4. Step 4: Simplify right side
   1,320.68x = 1,527,787.98
5. Step 5: Solve for x
   x = 1,527,787.98/1,320.68
6. Step 6: Final answer
   x = 1,156.82