Finding the Fourth Proportional to 128.10, 191.31 and 107.82

Step by Step Solution

1. Step 1: Write the proportion equation
   128.10 : 191.31 = 107.82 : x
2. Step 2: Convert to fraction form
   128.10/191.31 = 107.82/x
3. Step 3: Cross multiply
   128.10x = 191.31 × 107.82
4. Step 4: Simplify right side
   128.10x = 20,627.04
5. Step 5: Solve for x
   x = 20,627.04/128.10
6. Step 6: Final answer
   x = 161.02