Finding the Fourth Proportional to 1,010.72, 1,514.28 and 686.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,010.72 : 1,514.28 = 686.72 : x
2. Step 2: Convert to fraction form
   1,010.72/1,514.28 = 686.72/x
3. Step 3: Cross multiply
   1,010.72x = 1,514.28 × 686.72
4. Step 4: Simplify right side
   1,010.72x = 1,039,886.36
5. Step 5: Solve for x
   x = 1,039,886.36/1,010.72
6. Step 6: Final answer
   x = 1,028.86