Finding the Third Proportional to 172,196 and 258,290

Step by Step Solution

1. Step 1: Write the proportion equation
   172,196 : 258,290 = 258,290 : x
2. Step 2: Convert to fraction form
   172,196/258,290 = 258,290/x
3. Step 3: Cross multiply
   172,196x = 258,290 × 258,290
4. Step 4: Simplify right side
   172,196x = 66,713,724,100
5. Step 5: Solve for x
   x = 66,713,724,100/172,196
6. Step 6: Final answer
   x = 387,429.00