Finding the Fourth Proportional to 90.69, 135.97 and 42.56

Step by Step Solution

1. Step 1: Write the proportion equation
   90.69 : 135.97 = 42.56 : x
2. Step 2: Convert to fraction form
   90.69/135.97 = 42.56/x
3. Step 3: Cross multiply
   90.69x = 135.97 × 42.56
4. Step 4: Simplify right side
   90.69x = 5,787.12
5. Step 5: Solve for x
   x = 5,787.12/90.69
6. Step 6: Final answer
   x = 63.81