Finding the Third Proportional to 78,840 and 172,988

Step by Step Solution

1. Step 1: Write the proportion equation
   78,840 : 172,988 = 172,988 : x
2. Step 2: Convert to fraction form
   78,840/172,988 = 172,988/x
3. Step 3: Cross multiply
   78,840x = 172,988 × 172,988
4. Step 4: Simplify right side
   78,840x = 29,924,848,144
5. Step 5: Solve for x
   x = 29,924,848,144/78,840
6. Step 6: Final answer
   x = 379,564.28