Finding the Third Proportional to 660.66 and 989.72

Step by Step Solution

1. Step 1: Write the proportion equation
   660.66 : 989.72 = 989.72 : x
2. Step 2: Convert to fraction form
   660.66/989.72 = 989.72/x
3. Step 3: Cross multiply
   660.66x = 989.72 × 989.72
4. Step 4: Simplify right side
   660.66x = 979,543.20
5. Step 5: Solve for x
   x = 979,543.20/660.66
6. Step 6: Final answer
   x = 1,482.68