Finding the Fourth Proportional to 105.72, 145.87 and 70.69

Step by Step Solution

1. Step 1: Write the proportion equation
   105.72 : 145.87 = 70.69 : x
2. Step 2: Convert to fraction form
   105.72/145.87 = 70.69/x
3. Step 3: Cross multiply
   105.72x = 145.87 × 70.69
4. Step 4: Simplify right side
   105.72x = 10,311.27
5. Step 5: Solve for x
   x = 10,311.27/105.72
6. Step 6: Final answer
   x = 97.54