Finding the Fourth Proportional to 102.91, 141.96 and 71.79

Step by Step Solution

1. Step 1: Write the proportion equation
   102.91 : 141.96 = 71.79 : x
2. Step 2: Convert to fraction form
   102.91/141.96 = 71.79/x
3. Step 3: Cross multiply
   102.91x = 141.96 × 71.79
4. Step 4: Simplify right side
   102.91x = 10,191.31
5. Step 5: Solve for x
   x = 10,191.31/102.91
6. Step 6: Final answer
   x = 99.03