Finding the Third Proportional to 660,118.50 and 991,638

Step by Step Solution

1. Step 1: Write the proportion equation
   660,118.50 : 991,638 = 991,638 : x
2. Step 2: Convert to fraction form
   660,118.50/991,638 = 991,638/x
3. Step 3: Cross multiply
   660,118.50x = 991,638 × 991,638
4. Step 4: Simplify right side
   660,118.50x = 983,345,923,044
5. Step 5: Solve for x
   x = 983,345,923,044/660,118.50
6. Step 6: Final answer
   x = 1,489,650.61