Finding the Fourth Proportional to 1,236.72, 1,706.75 and 712.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,236.72 : 1,706.75 = 712.78 : x
2. Step 2: Convert to fraction form
   1,236.72/1,706.75 = 712.78/x
3. Step 3: Cross multiply
   1,236.72x = 1,706.75 × 712.78
4. Step 4: Simplify right side
   1,236.72x = 1,216,543.31
5. Step 5: Solve for x
   x = 1,216,543.31/1,236.72
6. Step 6: Final answer
   x = 983.69