Finding the Fourth Proportional to 117.50, 162.20 and 78.71

Step by Step Solution

1. Step 1: Write the proportion equation
   117.50 : 162.20 = 78.71 : x
2. Step 2: Convert to fraction form
   117.50/162.20 = 78.71/x
3. Step 3: Cross multiply
   117.50x = 162.20 × 78.71
4. Step 4: Simplify right side
   117.50x = 12,766.37
5. Step 5: Solve for x
   x = 12,766.37/117.50
6. Step 6: Final answer
   x = 108.65