Finding the Third Proportional to 61.88 and 128.69

Step by Step Solution

1. Step 1: Write the proportion equation
   61.88 : 128.69 = 128.69 : x
2. Step 2: Convert to fraction form
   61.88/128.69 = 128.69/x
3. Step 3: Cross multiply
   61.88x = 128.69 × 128.69
4. Step 4: Simplify right side
   61.88x = 16,560.47
5. Step 5: Solve for x
   x = 16,560.47/61.88
6. Step 6: Final answer
   x = 267.64