Finding the Fourth Proportional to 105.72, 145.89 and 70.71

Step by Step Solution

1. Step 1: Write the proportion equation
   105.72 : 145.89 = 70.71 : x
2. Step 2: Convert to fraction form
   105.72/145.89 = 70.71/x
3. Step 3: Cross multiply
   105.72x = 145.89 × 70.71
4. Step 4: Simplify right side
   105.72x = 10,315.88
5. Step 5: Solve for x
   x = 10,315.88/105.72
6. Step 6: Final answer
   x = 97.58