Finding the Fourth Proportional to 69.79, 96.31 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   69.79 : 96.31 = 42.15 : x
2. Step 2: Convert to fraction form
   69.79/96.31 = 42.15/x
3. Step 3: Cross multiply
   69.79x = 96.31 × 42.15
4. Step 4: Simplify right side
   69.79x = 4,059.80
5. Step 5: Solve for x
   x = 4,059.80/69.79
6. Step 6: Final answer
   x = 58.18