Finding the Fourth Proportional to 72.42, 108.72 and 71.70

Step by Step Solution

1. Step 1: Write the proportion equation
   72.42 : 108.72 = 71.70 : x
2. Step 2: Convert to fraction form
   72.42/108.72 = 71.70/x
3. Step 3: Cross multiply
   72.42x = 108.72 × 71.70
4. Step 4: Simplify right side
   72.42x = 7,795.22
5. Step 5: Solve for x
   x = 7,795.22/72.42
6. Step 6: Final answer
   x = 107.64