Finding the Fourth Proportional to 105.93, 158.16 and 90.72

Step by Step Solution

1. Step 1: Write the proportion equation
   105.93 : 158.16 = 90.72 : x
2. Step 2: Convert to fraction form
   105.93/158.16 = 90.72/x
3. Step 3: Cross multiply
   105.93x = 158.16 × 90.72
4. Step 4: Simplify right side
   105.93x = 14,348.28
5. Step 5: Solve for x
   x = 14,348.28/105.93
6. Step 6: Final answer
   x = 135.45