Finding the Fourth Proportional to 2,155.16, 2,974.09 and 1,223.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,155.16 : 2,974.09 = 1,223.60 : x
2. Step 2: Convert to fraction form
   2,155.16/2,974.09 = 1,223.60/x
3. Step 3: Cross multiply
   2,155.16x = 2,974.09 × 1,223.60
4. Step 4: Simplify right side
   2,155.16x = 3,639,096.52
5. Step 5: Solve for x
   x = 3,639,096.52/2,155.16
6. Step 6: Final answer
   x = 1,688.55