Finding the Fourth Proportional to 1,010.72, 1,517.86 and 664.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,010.72 : 1,517.86 = 664.76 : x
2. Step 2: Convert to fraction form
   1,010.72/1,517.86 = 664.76/x
3. Step 3: Cross multiply
   1,010.72x = 1,517.86 × 664.76
4. Step 4: Simplify right side
   1,010.72x = 1,009,012.61
5. Step 5: Solve for x
   x = 1,009,012.61/1,010.72
6. Step 6: Final answer
   x = 998.31