Finding the Fourth Proportional to 90.96, 136.28 and 42.12

Step by Step Solution

1. Step 1: Write the proportion equation
   90.96 : 136.28 = 42.12 : x
2. Step 2: Convert to fraction form
   90.96/136.28 = 42.12/x
3. Step 3: Cross multiply
   90.96x = 136.28 × 42.12
4. Step 4: Simplify right side
   90.96x = 5,739.90
5. Step 5: Solve for x
   x = 5,739.90/90.96
6. Step 6: Final answer
   x = 63.10