Finding the Fourth Proportional to 71.78, 107.61 and 50.05

Step by Step Solution

1. Step 1: Write the proportion equation
   71.78 : 107.61 = 50.05 : x
2. Step 2: Convert to fraction form
   71.78/107.61 = 50.05/x
3. Step 3: Cross multiply
   71.78x = 107.61 × 50.05
4. Step 4: Simplify right side
   71.78x = 5,386.25
5. Step 5: Solve for x
   x = 5,386.25/71.78
6. Step 6: Final answer
   x = 75.03