Finding the Fourth Proportional to 78.91, 108.73 and 65.19

Step by Step Solution

1. Step 1: Write the proportion equation
   78.91 : 108.73 = 65.19 : x
2. Step 2: Convert to fraction form
   78.91/108.73 = 65.19/x
3. Step 3: Cross multiply
   78.91x = 108.73 × 65.19
4. Step 4: Simplify right side
   78.91x = 7,087.24
5. Step 5: Solve for x
   x = 7,087.24/78.91
6. Step 6: Final answer
   x = 89.82