Finding the Third Proportional to 78,776 and 172,864

Step by Step Solution

1. Step 1: Write the proportion equation
   78,776 : 172,864 = 172,864 : x
2. Step 2: Convert to fraction form
   78,776/172,864 = 172,864/x
3. Step 3: Cross multiply
   78,776x = 172,864 × 172,864
4. Step 4: Simplify right side
   78,776x = 29,881,962,496
5. Step 5: Solve for x
   x = 29,881,962,496/78,776
6. Step 6: Final answer
   x = 379,328.25