Finding the Fourth Proportional to 105.67, 158.25 and 86.07

Step by Step Solution

1. Step 1: Write the proportion equation
   105.67 : 158.25 = 86.07 : x
2. Step 2: Convert to fraction form
   105.67/158.25 = 86.07/x
3. Step 3: Cross multiply
   105.67x = 158.25 × 86.07
4. Step 4: Simplify right side
   105.67x = 13,620.12
5. Step 5: Solve for x
   x = 13,620.12/105.67
6. Step 6: Final answer
   x = 128.89