Finding the Third Proportional to 78,388 and 172,328

Step by Step Solution

1. Step 1: Write the proportion equation
   78,388 : 172,328 = 172,328 : x
2. Step 2: Convert to fraction form
   78,388/172,328 = 172,328/x
3. Step 3: Cross multiply
   78,388x = 172,328 × 172,328
4. Step 4: Simplify right side
   78,388x = 29,696,939,584
5. Step 5: Solve for x
   x = 29,696,939,584/78,388
6. Step 6: Final answer
   x = 378,845.48