Finding the Fourth Proportional to 1,215.83, 1,677.78 and 684.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.83 : 1,677.78 = 684.72 : x
2. Step 2: Convert to fraction form
   1,215.83/1,677.78 = 684.72/x
3. Step 3: Cross multiply
   1,215.83x = 1,677.78 × 684.72
4. Step 4: Simplify right side
   1,215.83x = 1,148,809.52
5. Step 5: Solve for x
   x = 1,148,809.52/1,215.83
6. Step 6: Final answer
   x = 944.88