Finding the Third Proportional to 54.56 and 83.81

Step by Step Solution

1. Step 1: Write the proportion equation
   54.56 : 83.81 = 83.81 : x
2. Step 2: Convert to fraction form
   54.56/83.81 = 83.81/x
3. Step 3: Cross multiply
   54.56x = 83.81 × 83.81
4. Step 4: Simplify right side
   54.56x = 7,024.54
5. Step 5: Solve for x
   x = 7,024.54/54.56
6. Step 6: Final answer
   x = 128.74