Finding the Third Proportional to 42.40 and 82.90

Step by Step Solution

1. Step 1: Write the proportion equation
   42.40 : 82.90 = 82.90 : x
2. Step 2: Convert to fraction form
   42.40/82.90 = 82.90/x
3. Step 3: Cross multiply
   42.40x = 82.90 × 82.90
4. Step 4: Simplify right side
   42.40x = 6,872.15
5. Step 5: Solve for x
   x = 6,872.15/42.40
6. Step 6: Final answer
   x = 162.09