Finding the Fourth Proportional to 99.72, 137.48 and 82.15

Step by Step Solution

1. Step 1: Write the proportion equation
   99.72 : 137.48 = 82.15 : x
2. Step 2: Convert to fraction form
   99.72/137.48 = 82.15/x
3. Step 3: Cross multiply
   99.72x = 137.48 × 82.15
4. Step 4: Simplify right side
   99.72x = 11,293.23
5. Step 5: Solve for x
   x = 11,293.23/99.72
6. Step 6: Final answer
   x = 113.25