Finding the Fourth Proportional to 103.17, 142.29 and 72.18

Step by Step Solution

1. Step 1: Write the proportion equation
   103.17 : 142.29 = 72.18 : x
2. Step 2: Convert to fraction form
   103.17/142.29 = 72.18/x
3. Step 3: Cross multiply
   103.17x = 142.29 × 72.18
4. Step 4: Simplify right side
   103.17x = 10,270.49
5. Step 5: Solve for x
   x = 10,270.49/103.17
6. Step 6: Final answer
   x = 99.55