Finding the Third Proportional to 418,087.50 and 617,290.50

Step by Step Solution

1. Step 1: Write the proportion equation
   418,087.50 : 617,290.50 = 617,290.50 : x
2. Step 2: Convert to fraction form
   418,087.50/617,290.50 = 617,290.50/x
3. Step 3: Cross multiply
   418,087.50x = 617,290.50 × 617,290.50
4. Step 4: Simplify right side
   418,087.50x = 381,047,561,390.25
5. Step 5: Solve for x
   x = 381,047,561,390.25/418,087.50
6. Step 6: Final answer
   x = 911,406.25