Finding the Fourth Proportional to 90.27, 135.50 and 42.21

Step by Step Solution

1. Step 1: Write the proportion equation
   90.27 : 135.50 = 42.21 : x
2. Step 2: Convert to fraction form
   90.27/135.50 = 42.21/x
3. Step 3: Cross multiply
   90.27x = 135.50 × 42.21
4. Step 4: Simplify right side
   90.27x = 5,719.24
5. Step 5: Solve for x
   x = 5,719.24/90.27
6. Step 6: Final answer
   x = 63.36