Finding the Fourth Proportional to 71.91, 107.72 and 42.93

Step by Step Solution

1. Step 1: Write the proportion equation
   71.91 : 107.72 = 42.93 : x
2. Step 2: Convert to fraction form
   71.91/107.72 = 42.93/x
3. Step 3: Cross multiply
   71.91x = 107.72 × 42.93
4. Step 4: Simplify right side
   71.91x = 4,624.42
5. Step 5: Solve for x
   x = 4,624.42/71.91
6. Step 6: Final answer
   x = 64.31