Finding the Fourth Proportional to 109.81, 164.59 and 71.31

Step by Step Solution

1. Step 1: Write the proportion equation
   109.81 : 164.59 = 71.31 : x
2. Step 2: Convert to fraction form
   109.81/164.59 = 71.31/x
3. Step 3: Cross multiply
   109.81x = 164.59 × 71.31
4. Step 4: Simplify right side
   109.81x = 11,737.35
5. Step 5: Solve for x
   x = 11,737.35/109.81
6. Step 6: Final answer
   x = 106.89