Finding the Fourth Proportional to 78.89, 118.56 and 71.19

Step by Step Solution

1. Step 1: Write the proportion equation
   78.89 : 118.56 = 71.19 : x
2. Step 2: Convert to fraction form
   78.89/118.56 = 71.19/x
3. Step 3: Cross multiply
   78.89x = 118.56 × 71.19
4. Step 4: Simplify right side
   78.89x = 8,440.29
5. Step 5: Solve for x
   x = 8,440.29/78.89
6. Step 6: Final answer
   x = 106.99