Finding the Third Proportional to 66.78 and 144.56

Step by Step Solution

1. Step 1: Write the proportion equation
   66.78 : 144.56 = 144.56 : x
2. Step 2: Convert to fraction form
   66.78/144.56 = 144.56/x
3. Step 3: Cross multiply
   66.78x = 144.56 × 144.56
4. Step 4: Simplify right side
   66.78x = 20,898.32
5. Step 5: Solve for x
   x = 20,898.32/66.78
6. Step 6: Final answer
   x = 312.94