Finding the Fourth Proportional to 72.56, 108.72 and 45.42

Step by Step Solution

1. Step 1: Write the proportion equation
   72.56 : 108.72 = 45.42 : x
2. Step 2: Convert to fraction form
   72.56/108.72 = 45.42/x
3. Step 3: Cross multiply
   72.56x = 108.72 × 45.42
4. Step 4: Simplify right side
   72.56x = 4,938.06
5. Step 5: Solve for x
   x = 4,938.06/72.56
6. Step 6: Final answer
   x = 68.05