Finding the Fourth Proportional to 105.87, 145.88 and 71.31

Step by Step Solution

1. Step 1: Write the proportion equation
   105.87 : 145.88 = 71.31 : x
2. Step 2: Convert to fraction form
   105.87/145.88 = 71.31/x
3. Step 3: Cross multiply
   105.87x = 145.88 × 71.31
4. Step 4: Simplify right side
   105.87x = 10,402.35
5. Step 5: Solve for x
   x = 10,402.35/105.87
6. Step 6: Final answer
   x = 98.26