Finding the Fourth Proportional to 78.48, 108.09 and 65.34

Step by Step Solution

1. Step 1: Write the proportion equation
   78.48 : 108.09 = 65.34 : x
2. Step 2: Convert to fraction form
   78.48/108.09 = 65.34/x
3. Step 3: Cross multiply
   78.48x = 108.09 × 65.34
4. Step 4: Simplify right side
   78.48x = 7,062.06
5. Step 5: Solve for x
   x = 7,062.06/78.48
6. Step 6: Final answer
   x = 89.99