Finding the Third Proportional to 123,240 and 258,915

Step by Step Solution

1. Step 1: Write the proportion equation
   123,240 : 258,915 = 258,915 : x
2. Step 2: Convert to fraction form
   123,240/258,915 = 258,915/x
3. Step 3: Cross multiply
   123,240x = 258,915 × 258,915
4. Step 4: Simplify right side
   123,240x = 67,036,977,225
5. Step 5: Solve for x
   x = 67,036,977,225/123,240
6. Step 6: Final answer
   x = 543,954.70