Finding the Third Proportional to 31.31 and 80.91

Step by Step Solution

1. Step 1: Write the proportion equation
   31.31 : 80.91 = 80.91 : x
2. Step 2: Convert to fraction form
   31.31/80.91 = 80.91/x
3. Step 3: Cross multiply
   31.31x = 80.91 × 80.91
4. Step 4: Simplify right side
   31.31x = 6,545.82
5. Step 5: Solve for x
   x = 6,545.82/31.31
6. Step 6: Final answer
   x = 209.05