Finding the Fourth Proportional to 111.28, 153.61 and 71.99

Step by Step Solution

1. Step 1: Write the proportion equation
   111.28 : 153.61 = 71.99 : x
2. Step 2: Convert to fraction form
   111.28/153.61 = 71.99/x
3. Step 3: Cross multiply
   111.28x = 153.61 × 71.99
4. Step 4: Simplify right side
   111.28x = 11,058.38
5. Step 5: Solve for x
   x = 11,058.38/111.28
6. Step 6: Final answer
   x = 99.37