## mitchelsewbaran Group Title What is the length of line BD in the equilateral triangle ABC shown below? one year ago one year ago

1. mitchelsewbaran Group Title

2. cathyangs Group Title

It says 10, right? In which case, do you know the 30-60-90 special triangle? |dw:1346612914460:dw| This triangle also half of an equilateral triangle. 2x is the 'diagonal' side of one half of your triangle, so 2x=10. Do you have it?

3. mitchelsewbaran Group Title

x=5

4. mitchelsewbaran Group Title

so the answer is 5, right?

5. mitchelsewbaran Group Title

the length of line BD

6. cathyangs Group Title

Not quite. The right angle is made from the perpendicular line dashed line in the middle of your equilateral triangle. You need to orient yourself so that the 30-60-90 triangle is the right half of your triangle. so the length of BD is represented by $x \sqrt{3}$

7. mitchelsewbaran Group Title

so it's 5√(3)?

8. cathyangs Group Title

yes :) that's it!

9. mitchelsewbaran Group Title

thnx!