Finding the Fourth Proportional to 78.43, 108.15 and 50.78

Step by Step Solution

1. Step 1: Write the proportion equation
   78.43 : 108.15 = 50.78 : x
2. Step 2: Convert to fraction form
   78.43/108.15 = 50.78/x
3. Step 3: Cross multiply
   78.43x = 108.15 × 50.78
4. Step 4: Simplify right side
   78.43x = 5,491.86
5. Step 5: Solve for x
   x = 5,491.86/78.43
6. Step 6: Final answer
   x = 70.02