Finding the Third Proportional to 51.31 and 76.78

Step by Step Solution

1. Step 1: Write the proportion equation
   51.31 : 76.78 = 76.78 : x
2. Step 2: Convert to fraction form
   51.31/76.78 = 76.78/x
3. Step 3: Cross multiply
   51.31x = 76.78 × 76.78
4. Step 4: Simplify right side
   51.31x = 5,895.36
5. Step 5: Solve for x
   x = 5,895.36/51.31
6. Step 6: Final answer
   x = 114.89