Finding the Fourth Proportional to 105.61, 158.58 and 67.12

Step by Step Solution

1. Step 1: Write the proportion equation
   105.61 : 158.58 = 67.12 : x
2. Step 2: Convert to fraction form
   105.61/158.58 = 67.12/x
3. Step 3: Cross multiply
   105.61x = 158.58 × 67.12
4. Step 4: Simplify right side
   105.61x = 10,643.89
5. Step 5: Solve for x
   x = 10,643.89/105.61
6. Step 6: Final answer
   x = 100.78