Finding the Third Proportional to 78,679 and 172,910

Step by Step Solution

1. Step 1: Write the proportion equation
   78,679 : 172,910 = 172,910 : x
2. Step 2: Convert to fraction form
   78,679/172,910 = 172,910/x
3. Step 3: Cross multiply
   78,679x = 172,910 × 172,910
4. Step 4: Simplify right side
   78,679x = 29,897,868,100
5. Step 5: Solve for x
   x = 29,897,868,100/78,679
6. Step 6: Final answer
   x = 379,998.07