Finding the Third Proportional to 216.81 and 281.31

Step by Step Solution

1. Step 1: Write the proportion equation
   216.81 : 281.31 = 281.31 : x
2. Step 2: Convert to fraction form
   216.81/281.31 = 281.31/x
3. Step 3: Cross multiply
   216.81x = 281.31 × 281.31
4. Step 4: Simplify right side
   216.81x = 79,136.72
5. Step 5: Solve for x
   x = 79,136.72/216.81
6. Step 6: Final answer
   x = 365.00