Finding the Fourth Proportional to 78.96, 108.88 and 64.94

Step by Step Solution

1. Step 1: Write the proportion equation
   78.96 : 108.88 = 64.94 : x
2. Step 2: Convert to fraction form
   78.96/108.88 = 64.94/x
3. Step 3: Cross multiply
   78.96x = 108.88 × 64.94
4. Step 4: Simplify right side
   78.96x = 7,070.67
5. Step 5: Solve for x
   x = 7,070.67/78.96
6. Step 6: Final answer
   x = 89.55