Finding the Fourth Proportional to 128.50, 177.39 and 123.94

Step by Step Solution

1. Step 1: Write the proportion equation
   128.50 : 177.39 = 123.94 : x
2. Step 2: Convert to fraction form
   128.50/177.39 = 123.94/x
3. Step 3: Cross multiply
   128.50x = 177.39 × 123.94
4. Step 4: Simplify right side
   128.50x = 21,985.72
5. Step 5: Solve for x
   x = 21,985.72/128.50
6. Step 6: Final answer
   x = 171.10