Finding the Third Proportional to 139.76 and 300.61

Step by Step Solution

1. Step 1: Write the proportion equation
   139.76 : 300.61 = 300.61 : x
2. Step 2: Convert to fraction form
   139.76/300.61 = 300.61/x
3. Step 3: Cross multiply
   139.76x = 300.61 × 300.61
4. Step 4: Simplify right side
   139.76x = 90,363.79
5. Step 5: Solve for x
   x = 90,363.79/139.76
6. Step 6: Final answer
   x = 646.58