Finding the Fourth Proportional to 78.98, 109.02 and 51.42

Step by Step Solution

1. Step 1: Write the proportion equation
   78.98 : 109.02 = 51.42 : x
2. Step 2: Convert to fraction form
   78.98/109.02 = 51.42/x
3. Step 3: Cross multiply
   78.98x = 109.02 × 51.42
4. Step 4: Simplify right side
   78.98x = 5,605.81
5. Step 5: Solve for x
   x = 5,605.81/78.98
6. Step 6: Final answer
   x = 70.98