Finding the Fourth Proportional to 72.21, 99.69 and 53.61

Step by Step Solution

1. Step 1: Write the proportion equation
   72.21 : 99.69 = 53.61 : x
2. Step 2: Convert to fraction form
   72.21/99.69 = 53.61/x
3. Step 3: Cross multiply
   72.21x = 99.69 × 53.61
4. Step 4: Simplify right side
   72.21x = 5,344.38
5. Step 5: Solve for x
   x = 5,344.38/72.21
6. Step 6: Final answer
   x = 74.01