Finding the Fourth Proportional to 105.84, 158.37 and 90.42

Step by Step Solution

1. Step 1: Write the proportion equation
   105.84 : 158.37 = 90.42 : x
2. Step 2: Convert to fraction form
   105.84/158.37 = 90.42/x
3. Step 3: Cross multiply
   105.84x = 158.37 × 90.42
4. Step 4: Simplify right side
   105.84x = 14,319.82
5. Step 5: Solve for x
   x = 14,319.82/105.84
6. Step 6: Final answer
   x = 135.30