Finding the Third Proportional to 51.26 and 78.31

Step by Step Solution

1. Step 1: Write the proportion equation
   51.26 : 78.31 = 78.31 : x
2. Step 2: Convert to fraction form
   51.26/78.31 = 78.31/x
3. Step 3: Cross multiply
   51.26x = 78.31 × 78.31
4. Step 4: Simplify right side
   51.26x = 6,132.54
5. Step 5: Solve for x
   x = 6,132.54/51.26
6. Step 6: Final answer
   x = 119.64