Finding the Fourth Proportional to 78.18, 107.90 and 50.56

Step by Step Solution

1. Step 1: Write the proportion equation
   78.18 : 107.90 = 50.56 : x
2. Step 2: Convert to fraction form
   78.18/107.90 = 50.56/x
3. Step 3: Cross multiply
   78.18x = 107.90 × 50.56
4. Step 4: Simplify right side
   78.18x = 5,455.42
5. Step 5: Solve for x
   x = 5,455.42/78.18
6. Step 6: Final answer
   x = 69.78