Finding the Fourth Proportional to 80.72, 111.40 and 53.10

Step by Step Solution

1. Step 1: Write the proportion equation
   80.72 : 111.40 = 53.10 : x
2. Step 2: Convert to fraction form
   80.72/111.40 = 53.10/x
3. Step 3: Cross multiply
   80.72x = 111.40 × 53.10
4. Step 4: Simplify right side
   80.72x = 5,915.34
5. Step 5: Solve for x
   x = 5,915.34/80.72
6. Step 6: Final answer
   x = 73.28