Finding the Fourth Proportional to 128.72, 194.36 and 128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   128.72 : 194.36 = 128.72 : x
2. Step 2: Convert to fraction form
   128.72/194.36 = 128.72/x
3. Step 3: Cross multiply
   128.72x = 194.36 × 128.72
4. Step 4: Simplify right side
   128.72x = 25,018.02
5. Step 5: Solve for x
   x = 25,018.02/128.72
6. Step 6: Final answer
   x = 194.36