Finding the Fourth Proportional to 103.34, 142.49 and 72.20

Step by Step Solution

1. Step 1: Write the proportion equation
   103.34 : 142.49 = 72.20 : x
2. Step 2: Convert to fraction form
   103.34/142.49 = 72.20/x
3. Step 3: Cross multiply
   103.34x = 142.49 × 72.20
4. Step 4: Simplify right side
   103.34x = 10,288.31
5. Step 5: Solve for x
   x = 10,288.31/103.34
6. Step 6: Final answer
   x = 99.56