Finding the Fourth Proportional to 1,931.58, 2,666.79 and 1,223.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,931.58 : 2,666.79 = 1,223.78 : x
2. Step 2: Convert to fraction form
   1,931.58/2,666.79 = 1,223.78/x
3. Step 3: Cross multiply
   1,931.58x = 2,666.79 × 1,223.78
4. Step 4: Simplify right side
   1,931.58x = 3,263,550.93
5. Step 5: Solve for x
   x = 3,263,550.93/1,931.58
6. Step 6: Final answer
   x = 1,689.58