Finding the Fourth Proportional to 1,205.76, 1,664.28 and 1,123.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,205.76 : 1,664.28 = 1,123.68 : x
2. Step 2: Convert to fraction form
   1,205.76/1,664.28 = 1,123.68/x
3. Step 3: Cross multiply
   1,205.76x = 1,664.28 × 1,123.68
4. Step 4: Simplify right side
   1,205.76x = 1,870,118.15
5. Step 5: Solve for x
   x = 1,870,118.15/1,205.76
6. Step 6: Final answer
   x = 1,550.99