Finding the Third Proportional to 645,344 and 990,300

Step by Step Solution

1. Step 1: Write the proportion equation
   645,344 : 990,300 = 990,300 : x
2. Step 2: Convert to fraction form
   645,344/990,300 = 990,300/x
3. Step 3: Cross multiply
   645,344x = 990,300 × 990,300
4. Step 4: Simplify right side
   645,344x = 980,694,090,000
5. Step 5: Solve for x
   x = 980,694,090,000/645,344
6. Step 6: Final answer
   x = 1,519,645.48