Finding the Fourth Proportional to 78.83, 108.78 and 51.18

Step by Step Solution

1. Step 1: Write the proportion equation
   78.83 : 108.78 = 51.18 : x
2. Step 2: Convert to fraction form
   78.83/108.78 = 51.18/x
3. Step 3: Cross multiply
   78.83x = 108.78 × 51.18
4. Step 4: Simplify right side
   78.83x = 5,567.36
5. Step 5: Solve for x
   x = 5,567.36/78.83
6. Step 6: Final answer
   x = 70.62