Finding the Fourth Proportional to 109.20, 159.72 and 109.20

Step by Step Solution

1. Step 1: Write the proportion equation
   109.20 : 159.72 = 109.20 : x
2. Step 2: Convert to fraction form
   109.20/159.72 = 109.20/x
3. Step 3: Cross multiply
   109.20x = 159.72 × 109.20
4. Step 4: Simplify right side
   109.20x = 17,441.42
5. Step 5: Solve for x
   x = 17,441.42/109.20
6. Step 6: Final answer
   x = 159.72