Finding the Third Proportional to 42.25 and 72

Step by Step Solution

1. Step 1: Write the proportion equation
   42.25 : 72 = 72 : x
2. Step 2: Convert to fraction form
   42.25/72 = 72/x
3. Step 3: Cross multiply
   42.25x = 72 × 72
4. Step 4: Simplify right side
   42.25x = 5,184
5. Step 5: Solve for x
   x = 5,184/42.25
6. Step 6: Final answer
   x = 122.70