Finding the Third Proportional to 275,815.50 and 428,839.50

Step by Step Solution

1. Step 1: Write the proportion equation
   275,815.50 : 428,839.50 = 428,839.50 : x
2. Step 2: Convert to fraction form
   275,815.50/428,839.50 = 428,839.50/x
3. Step 3: Cross multiply
   275,815.50x = 428,839.50 × 428,839.50
4. Step 4: Simplify right side
   275,815.50x = 183,903,316,760.25
5. Step 5: Solve for x
   x = 183,903,316,760.25/275,815.50
6. Step 6: Final answer
   x = 666,762.08