Finding the Fourth Proportional to 1,780.61, 2,670.55 and 684.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,780.61 : 2,670.55 = 684.72 : x
2. Step 2: Convert to fraction form
   1,780.61/2,670.55 = 684.72/x
3. Step 3: Cross multiply
   1,780.61x = 2,670.55 × 684.72
4. Step 4: Simplify right side
   1,780.61x = 1,828,577.28
5. Step 5: Solve for x
   x = 1,828,577.28/1,780.61
6. Step 6: Final answer
   x = 1,026.94