Finding the Fourth Proportional to 105.08, 145.04 and 71.91

Step by Step Solution

1. Step 1: Write the proportion equation
   105.08 : 145.04 = 71.91 : x
2. Step 2: Convert to fraction form
   105.08/145.04 = 71.91/x
3. Step 3: Cross multiply
   105.08x = 145.04 × 71.91
4. Step 4: Simplify right side
   105.08x = 10,429.47
5. Step 5: Solve for x
   x = 10,429.47/105.08
6. Step 6: Final answer
   x = 99.26