Finding the Fourth Proportional to 90.36, 135.34 and 42.12

Step by Step Solution

1. Step 1: Write the proportion equation
   90.36 : 135.34 = 42.12 : x
2. Step 2: Convert to fraction form
   90.36/135.34 = 42.12/x
3. Step 3: Cross multiply
   90.36x = 135.34 × 42.12
4. Step 4: Simplify right side
   90.36x = 5,700.52
5. Step 5: Solve for x
   x = 5,700.52/90.36
6. Step 6: Final answer
   x = 63.09