Finding the Fourth Proportional to 128.22, 191.42 and 123.72

Step by Step Solution

1. Step 1: Write the proportion equation
   128.22 : 191.42 = 123.72 : x
2. Step 2: Convert to fraction form
   128.22/191.42 = 123.72/x
3. Step 3: Cross multiply
   128.22x = 191.42 × 123.72
4. Step 4: Simplify right side
   128.22x = 23,682.48
5. Step 5: Solve for x
   x = 23,682.48/128.22
6. Step 6: Final answer
   x = 184.70