Finding the Fourth Proportional to 1,780.72, 2,671.20 and 684.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,780.72 : 2,671.20 = 684.72 : x
2. Step 2: Convert to fraction form
   1,780.72/2,671.20 = 684.72/x
3. Step 3: Cross multiply
   1,780.72x = 2,671.20 × 684.72
4. Step 4: Simplify right side
   1,780.72x = 1,829,024.06
5. Step 5: Solve for x
   x = 1,829,024.06/1,780.72
6. Step 6: Final answer
   x = 1,027.13