Finding the Fourth Proportional to 1,120.89, 1,546.58 and 678.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,120.89 : 1,546.58 = 678.78 : x
2. Step 2: Convert to fraction form
   1,120.89/1,546.58 = 678.78/x
3. Step 3: Cross multiply
   1,120.89x = 1,546.58 × 678.78
4. Step 4: Simplify right side
   1,120.89x = 1,049,792.52
5. Step 5: Solve for x
   x = 1,049,792.52/1,120.89
6. Step 6: Final answer
   x = 936.57