Finding the Fourth Proportional to 71.82, 107.72 and 47.78

Step by Step Solution

1. Step 1: Write the proportion equation
   71.82 : 107.72 = 47.78 : x
2. Step 2: Convert to fraction form
   71.82/107.72 = 47.78/x
3. Step 3: Cross multiply
   71.82x = 107.72 × 47.78
4. Step 4: Simplify right side
   71.82x = 5,146.86
5. Step 5: Solve for x
   x = 5,146.86/71.82
6. Step 6: Final answer
   x = 71.66