Finding the Fourth Proportional to 128.72, 192.56 and 116.72

Step by Step Solution

1. Step 1: Write the proportion equation
   128.72 : 192.56 = 116.72 : x
2. Step 2: Convert to fraction form
   128.72/192.56 = 116.72/x
3. Step 3: Cross multiply
   128.72x = 192.56 × 116.72
4. Step 4: Simplify right side
   128.72x = 22,475.60
5. Step 5: Solve for x
   x = 22,475.60/128.72
6. Step 6: Final answer
   x = 174.61