Finding the Fourth Proportional to 128.05, 176.69 and 72.03

Step by Step Solution

1. Step 1: Write the proportion equation
   128.05 : 176.69 = 72.03 : x
2. Step 2: Convert to fraction form
   128.05/176.69 = 72.03/x
3. Step 3: Cross multiply
   128.05x = 176.69 × 72.03
4. Step 4: Simplify right side
   128.05x = 12,726.98
5. Step 5: Solve for x
   x = 12,726.98/128.05
6. Step 6: Final answer
   x = 99.39