Finding the Third Proportional to 688,436 and 991,540

Step by Step Solution

1. Step 1: Write the proportion equation
   688,436 : 991,540 = 991,540 : x
2. Step 2: Convert to fraction form
   688,436/991,540 = 991,540/x
3. Step 3: Cross multiply
   688,436x = 991,540 × 991,540
4. Step 4: Simplify right side
   688,436x = 983,151,571,600
5. Step 5: Solve for x
   x = 983,151,571,600/688,436
6. Step 6: Final answer
   x = 1,428,094.36