Finding the Fourth Proportional to 1,144.80, 1,579.20 and 678.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,144.80 : 1,579.20 = 678.72 : x
2. Step 2: Convert to fraction form
   1,144.80/1,579.20 = 678.72/x
3. Step 3: Cross multiply
   1,144.80x = 1,579.20 × 678.72
4. Step 4: Simplify right side
   1,144.80x = 1,071,834.62
5. Step 5: Solve for x
   x = 1,071,834.62/1,144.80
6. Step 6: Final answer
   x = 936.26