Finding the Third Proportional to 140.56 and 209.56

Step by Step Solution

1. Step 1: Write the proportion equation
   140.56 : 209.56 = 209.56 : x
2. Step 2: Convert to fraction form
   140.56/209.56 = 209.56/x
3. Step 3: Cross multiply
   140.56x = 209.56 × 209.56
4. Step 4: Simplify right side
   140.56x = 43,916.44
5. Step 5: Solve for x
   x = 43,916.44/140.56
6. Step 6: Final answer
   x = 312.43