Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
I just want to share a rule about the triangle. I hope most [#permalink]
29 May 2007, 09:54
I just want to share a rule about the triangle. I hope most of you already know about it.
The area of the triangle, which has the midpoints of the sides of some triangle x as vertices is the one fourth of the area of triangle x.
Proof: Say the big triangle is - triangle x
small triangle is - triangle y
the area of the triangle x = sqrt[s(s-a)(s-b)(s-c)] where s = semi perimeter of the triangle x = (a+b+c)/2
semi perimeter of triangle y will be s/2
so area of the small triangle = 1/4 of the area of triangle x