Finding the Fourth Proportional to 103.16, 142.29 and 72.09

Step by Step Solution

1. Step 1: Write the proportion equation
   103.16 : 142.29 = 72.09 : x
2. Step 2: Convert to fraction form
   103.16/142.29 = 72.09/x
3. Step 3: Cross multiply
   103.16x = 142.29 × 72.09
4. Step 4: Simplify right side
   103.16x = 10,257.69
5. Step 5: Solve for x
   x = 10,257.69/103.16
6. Step 6: Final answer
   x = 99.43