Finding the Fourth Proportional to 105.78, 158.72 and 87.96

Step by Step Solution

1. Step 1: Write the proportion equation
   105.78 : 158.72 = 87.96 : x
2. Step 2: Convert to fraction form
   105.78/158.72 = 87.96/x
3. Step 3: Cross multiply
   105.78x = 158.72 × 87.96
4. Step 4: Simplify right side
   105.78x = 13,961.01
5. Step 5: Solve for x
   x = 13,961.01/105.78
6. Step 6: Final answer
   x = 131.98