Finding the Fourth Proportional to 93.25, 128.72 and 56.42

Step by Step Solution

1. Step 1: Write the proportion equation
   93.25 : 128.72 = 56.42 : x
2. Step 2: Convert to fraction form
   93.25/128.72 = 56.42/x
3. Step 3: Cross multiply
   93.25x = 128.72 × 56.42
4. Step 4: Simplify right side
   93.25x = 7,262.38
5. Step 5: Solve for x
   x = 7,262.38/93.25
6. Step 6: Final answer
   x = 77.88