Finding the Fourth Proportional to 1,007.98, 1,510.25 and 660.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.98 : 1,510.25 = 660.89 : x
2. Step 2: Convert to fraction form
   1,007.98/1,510.25 = 660.89/x
3. Step 3: Cross multiply
   1,007.98x = 1,510.25 × 660.89
4. Step 4: Simplify right side
   1,007.98x = 998,109.59
5. Step 5: Solve for x
   x = 998,109.59/1,007.98
6. Step 6: Final answer
   x = 990.21