Finding the Fourth Proportional to 104.90, 144.89 and 72.09

Step by Step Solution

1. Step 1: Write the proportion equation
   104.90 : 144.89 = 72.09 : x
2. Step 2: Convert to fraction form
   104.90/144.89 = 72.09/x
3. Step 3: Cross multiply
   104.90x = 144.89 × 72.09
4. Step 4: Simplify right side
   104.90x = 10,445.30
5. Step 5: Solve for x
   x = 10,445.30/104.90
6. Step 6: Final answer
   x = 99.58