Finding the Fourth Proportional to 79.30, 109.42 and 54.78

Step by Step Solution

1. Step 1: Write the proportion equation
   79.30 : 109.42 = 54.78 : x
2. Step 2: Convert to fraction form
   79.30/109.42 = 54.78/x
3. Step 3: Cross multiply
   79.30x = 109.42 × 54.78
4. Step 4: Simplify right side
   79.30x = 5,994.03
5. Step 5: Solve for x
   x = 5,994.03/79.30
6. Step 6: Final answer
   x = 75.59