Finding the Fourth Proportional to 128.09, 176.75 and 72.82

Step by Step Solution

1. Step 1: Write the proportion equation
   128.09 : 176.75 = 72.82 : x
2. Step 2: Convert to fraction form
   128.09/176.75 = 72.82/x
3. Step 3: Cross multiply
   128.09x = 176.75 × 72.82
4. Step 4: Simplify right side
   128.09x = 12,870.94
5. Step 5: Solve for x
   x = 12,870.94/128.09
6. Step 6: Final answer
   x = 100.48