Finding the Fourth Proportional to 90.63, 135.73 and 42.55

Step by Step Solution

1. Step 1: Write the proportion equation
   90.63 : 135.73 = 42.55 : x
2. Step 2: Convert to fraction form
   90.63/135.73 = 42.55/x
3. Step 3: Cross multiply
   90.63x = 135.73 × 42.55
4. Step 4: Simplify right side
   90.63x = 5,775.10
5. Step 5: Solve for x
   x = 5,775.10/90.63
6. Step 6: Final answer
   x = 63.72