Finding the Fourth Proportional to 128.12, 191.43 and 105.03

Step by Step Solution

1. Step 1: Write the proportion equation
   128.12 : 191.43 = 105.03 : x
2. Step 2: Convert to fraction form
   128.12/191.43 = 105.03/x
3. Step 3: Cross multiply
   128.12x = 191.43 × 105.03
4. Step 4: Simplify right side
   128.12x = 20,105.89
5. Step 5: Solve for x
   x = 20,105.89/128.12
6. Step 6: Final answer
   x = 156.94