Finding the Fourth Proportional to 78.89, 108.81 and 51.30

Step by Step Solution

1. Step 1: Write the proportion equation
   78.89 : 108.81 = 51.30 : x
2. Step 2: Convert to fraction form
   78.89/108.81 = 51.30/x
3. Step 3: Cross multiply
   78.89x = 108.81 × 51.30
4. Step 4: Simplify right side
   78.89x = 5,581.95
5. Step 5: Solve for x
   x = 5,581.95/78.89
6. Step 6: Final answer
   x = 70.76