Finding the Fourth Proportional to 81.10, 111.32 and 71.69

Step by Step Solution

1. Step 1: Write the proportion equation
   81.10 : 111.32 = 71.69 : x
2. Step 2: Convert to fraction form
   81.10/111.32 = 71.69/x
3. Step 3: Cross multiply
   81.10x = 111.32 × 71.69
4. Step 4: Simplify right side
   81.10x = 7,980.29
5. Step 5: Solve for x
   x = 7,980.29/81.10
6. Step 6: Final answer
   x = 98.40