Finding the Third Proportional to 99.67 and 206.30

Step by Step Solution

1. Step 1: Write the proportion equation
   99.67 : 206.30 = 206.30 : x
2. Step 2: Convert to fraction form
   99.67/206.30 = 206.30/x
3. Step 3: Cross multiply
   99.67x = 206.30 × 206.30
4. Step 4: Simplify right side
   99.67x = 42,558.40
5. Step 5: Solve for x
   x = 42,558.40/99.67
6. Step 6: Final answer
   x = 427.00