Finding the Fourth Proportional to 1,272.16, 1,905.82 and 724.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,272.16 : 1,905.82 = 724.72 : x
2. Step 2: Convert to fraction form
   1,272.16/1,905.82 = 724.72/x
3. Step 3: Cross multiply
   1,272.16x = 1,905.82 × 724.72
4. Step 4: Simplify right side
   1,272.16x = 1,381,185.87
5. Step 5: Solve for x
   x = 1,381,185.87/1,272.16
6. Step 6: Final answer
   x = 1,085.70