Finding the Fourth Proportional to 78.79, 108.71 and 47.72

Step by Step Solution

1. Step 1: Write the proportion equation
   78.79 : 108.71 = 47.72 : x
2. Step 2: Convert to fraction form
   78.79/108.71 = 47.72/x
3. Step 3: Cross multiply
   78.79x = 108.71 × 47.72
4. Step 4: Simplify right side
   78.79x = 5,187.64
5. Step 5: Solve for x
   x = 5,187.64/78.79
6. Step 6: Final answer
   x = 65.84