Finding the Fourth Proportional to 78.16, 107.89 and 50.55

Step by Step Solution

1. Step 1: Write the proportion equation
   78.16 : 107.89 = 50.55 : x
2. Step 2: Convert to fraction form
   78.16/107.89 = 50.55/x
3. Step 3: Cross multiply
   78.16x = 107.89 × 50.55
4. Step 4: Simplify right side
   78.16x = 5,453.84
5. Step 5: Solve for x
   x = 5,453.84/78.16
6. Step 6: Final answer
   x = 69.78