Finding the Fourth Proportional to 78.98, 109 and 51.37

Step by Step Solution

1. Step 1: Write the proportion equation
   78.98 : 109 = 51.37 : x
2. Step 2: Convert to fraction form
   78.98/109 = 51.37/x
3. Step 3: Cross multiply
   78.98x = 109 × 51.37
4. Step 4: Simplify right side
   78.98x = 5,599.33
5. Step 5: Solve for x
   x = 5,599.33/78.98
6. Step 6: Final answer
   x = 70.90