Finding the Fourth Proportional to 78.94, 109.04 and 64.56

Step by Step Solution

1. Step 1: Write the proportion equation
   78.94 : 109.04 = 64.56 : x
2. Step 2: Convert to fraction form
   78.94/109.04 = 64.56/x
3. Step 3: Cross multiply
   78.94x = 109.04 × 64.56
4. Step 4: Simplify right side
   78.94x = 7,039.62
5. Step 5: Solve for x
   x = 7,039.62/78.94
6. Step 6: Final answer
   x = 89.18