Finding the Third Proportional to 172.60 and 344.72

Step by Step Solution

1. Step 1: Write the proportion equation
   172.60 : 344.72 = 344.72 : x
2. Step 2: Convert to fraction form
   172.60/344.72 = 344.72/x
3. Step 3: Cross multiply
   172.60x = 344.72 × 344.72
4. Step 4: Simplify right side
   172.60x = 118,835.06
5. Step 5: Solve for x
   x = 118,835.06/172.60
6. Step 6: Final answer
   x = 688.50