Finding the Third Proportional to 19.10 and 39.31

Step by Step Solution

1. Step 1: Write the proportion equation
   19.10 : 39.31 = 39.31 : x
2. Step 2: Convert to fraction form
   19.10/39.31 = 39.31/x
3. Step 3: Cross multiply
   19.10x = 39.31 × 39.31
4. Step 4: Simplify right side
   19.10x = 1,545.55
5. Step 5: Solve for x
   x = 1,545.55/19.10
6. Step 6: Final answer
   x = 80.91