Finding the Fourth Proportional to 1,120.98, 1,546.71 and 678.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,120.98 : 1,546.71 = 678.90 : x
2. Step 2: Convert to fraction form
   1,120.98/1,546.71 = 678.90/x
3. Step 3: Cross multiply
   1,120.98x = 1,546.71 × 678.90
4. Step 4: Simplify right side
   1,120.98x = 1,050,061.42
5. Step 5: Solve for x
   x = 1,050,061.42/1,120.98
6. Step 6: Final answer
   x = 936.74