Finding the Third Proportional to 99.67 and 212.15

Step by Step Solution

1. Step 1: Write the proportion equation
   99.67 : 212.15 = 212.15 : x
2. Step 2: Convert to fraction form
   99.67/212.15 = 212.15/x
3. Step 3: Cross multiply
   99.67x = 212.15 × 212.15
4. Step 4: Simplify right side
   99.67x = 45,007.79
5. Step 5: Solve for x
   x = 45,007.79/99.67
6. Step 6: Final answer
   x = 451.58