Finding the Third Proportional to 172,620 and 258,210

Step by Step Solution

1. Step 1: Write the proportion equation
   172,620 : 258,210 = 258,210 : x
2. Step 2: Convert to fraction form
   172,620/258,210 = 258,210/x
3. Step 3: Cross multiply
   172,620x = 258,210 × 258,210
4. Step 4: Simplify right side
   172,620x = 66,672,404,100
5. Step 5: Solve for x
   x = 66,672,404,100/172,620
6. Step 6: Final answer
   x = 386,238.00