Finding the Fourth Proportional to 109.10, 150.50 and 72.20

Step by Step Solution

1. Step 1: Write the proportion equation
   109.10 : 150.50 = 72.20 : x
2. Step 2: Convert to fraction form
   109.10/150.50 = 72.20/x
3. Step 3: Cross multiply
   109.10x = 150.50 × 72.20
4. Step 4: Simplify right side
   109.10x = 10,866.10
5. Step 5: Solve for x
   x = 10,866.10/109.10
6. Step 6: Final answer
   x = 99.60