Finding the Fourth Proportional to 117.56, 162.18 and 78.72

Step by Step Solution

1. Step 1: Write the proportion equation
   117.56 : 162.18 = 78.72 : x
2. Step 2: Convert to fraction form
   117.56/162.18 = 78.72/x
3. Step 3: Cross multiply
   117.56x = 162.18 × 78.72
4. Step 4: Simplify right side
   117.56x = 12,766.81
5. Step 5: Solve for x
   x = 12,766.81/117.56
6. Step 6: Final answer
   x = 108.60