Finding the Fourth Proportional to 90.45, 135.56 and 42.25

Step by Step Solution

1. Step 1: Write the proportion equation
   90.45 : 135.56 = 42.25 : x
2. Step 2: Convert to fraction form
   90.45/135.56 = 42.25/x
3. Step 3: Cross multiply
   90.45x = 135.56 × 42.25
4. Step 4: Simplify right side
   90.45x = 5,727.41
5. Step 5: Solve for x
   x = 5,727.41/90.45
6. Step 6: Final answer
   x = 63.32