Finding the Third Proportional to 19.66 and 42.31

Step by Step Solution

1. Step 1: Write the proportion equation
   19.66 : 42.31 = 42.31 : x
2. Step 2: Convert to fraction form
   19.66/42.31 = 42.31/x
3. Step 3: Cross multiply
   19.66x = 42.31 × 42.31
4. Step 4: Simplify right side
   19.66x = 1,790.35
5. Step 5: Solve for x
   x = 1,790.35/19.66
6. Step 6: Final answer
   x = 91.08