Finding the Third Proportional to 56.75 and 128.38

Step by Step Solution

1. Step 1: Write the proportion equation
   56.75 : 128.38 = 128.38 : x
2. Step 2: Convert to fraction form
   56.75/128.38 = 128.38/x
3. Step 3: Cross multiply
   56.75x = 128.38 × 128.38
4. Step 4: Simplify right side
   56.75x = 16,480.14
5. Step 5: Solve for x
   x = 16,480.14/56.75
6. Step 6: Final answer
   x = 290.40