Finding the Fourth Proportional to 1,121.32, 1,678.78 and 890.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,121.32 : 1,678.78 = 890.54 : x
2. Step 2: Convert to fraction form
   1,121.32/1,678.78 = 890.54/x
3. Step 3: Cross multiply
   1,121.32x = 1,678.78 × 890.54
4. Step 4: Simplify right side
   1,121.32x = 1,495,019.76
5. Step 5: Solve for x
   x = 1,495,019.76/1,121.32
6. Step 6: Final answer
   x = 1,333.27