Finding the Fourth Proportional to 90.72, 135.96 and 42.54

Step by Step Solution

1. Step 1: Write the proportion equation
   90.72 : 135.96 = 42.54 : x
2. Step 2: Convert to fraction form
   90.72/135.96 = 42.54/x
3. Step 3: Cross multiply
   90.72x = 135.96 × 42.54
4. Step 4: Simplify right side
   90.72x = 5,783.74
5. Step 5: Solve for x
   x = 5,783.74/90.72
6. Step 6: Final answer
   x = 63.75