Finding the Fourth Proportional to 1,931.79, 2,664.78 and 1,223.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,931.79 : 2,664.78 = 1,223.42 : x
2. Step 2: Convert to fraction form
   1,931.79/2,664.78 = 1,223.42/x
3. Step 3: Cross multiply
   1,931.79x = 2,664.78 × 1,223.42
4. Step 4: Simplify right side
   1,931.79x = 3,260,145.15
5. Step 5: Solve for x
   x = 3,260,145.15/1,931.79
6. Step 6: Final answer
   x = 1,687.63