Finding the Fourth Proportional to 78.93, 108.84 and 51.31

Step by Step Solution

1. Step 1: Write the proportion equation
   78.93 : 108.84 = 51.31 : x
2. Step 2: Convert to fraction form
   78.93/108.84 = 51.31/x
3. Step 3: Cross multiply
   78.93x = 108.84 × 51.31
4. Step 4: Simplify right side
   78.93x = 5,583.78
5. Step 5: Solve for x
   x = 5,583.78/78.93
6. Step 6: Final answer
   x = 70.75