Finding the Fourth Proportional to 78.76, 109.42 and 78.06

Step by Step Solution

1. Step 1: Write the proportion equation
   78.76 : 109.42 = 78.06 : x
2. Step 2: Convert to fraction form
   78.76/109.42 = 78.06/x
3. Step 3: Cross multiply
   78.76x = 109.42 × 78.06
4. Step 4: Simplify right side
   78.76x = 8,541.33
5. Step 5: Solve for x
   x = 8,541.33/78.76
6. Step 6: Final answer
   x = 108.45