Finding the Fourth Proportional to 128.42, 192.76 and 56.34

Step by Step Solution

1. Step 1: Write the proportion equation
   128.42 : 192.76 = 56.34 : x
2. Step 2: Convert to fraction form
   128.42/192.76 = 56.34/x
3. Step 3: Cross multiply
   128.42x = 192.76 × 56.34
4. Step 4: Simplify right side
   128.42x = 10,860.10
5. Step 5: Solve for x
   x = 10,860.10/128.42
6. Step 6: Final answer
   x = 84.57