If M & N are midpoints of AC & DF resply. then MN=(d+f)/2. And in similar triangles NMG & BEG we've BE/MN = BG/MG = 2. Thus BE = e = 2MN =d + f Thanks for the hint, AG! Ajit: ajitathle@gmail.com
- Define H as the intersection of BG and AC - G centroid => H is in the middle of AC - Define I in DF with IH ⊥ DF - DA//FC//IH and H middle of AC => IH=(d+f)/2 - GIH is similar to GEB (aa) - =>GB/GH=EB/IH - GH=BH/3 and GB=2 BH/3 => GB=2GH - Therefore and EB=2IH, e=2(d+f)/2 - e=d+f
Hints:
ReplyDeleteThe median MN of the trapezoid ADFC.
Triangle NMG similar to triangle BEG.
If M & N are midpoints of AC & DF resply. then MN=(d+f)/2. And in similar triangles NMG & BEG we've BE/MN = BG/MG = 2. Thus BE = e = 2MN =d + f
ReplyDeleteThanks for the hint, AG!
Ajit: ajitathle@gmail.com
See the drawing
ReplyDelete- Define H as the intersection of BG and AC
- G centroid => H is in the middle of AC
- Define I in DF with IH ⊥ DF
- DA//FC//IH and H middle of AC => IH=(d+f)/2
- GIH is similar to GEB (aa)
- =>GB/GH=EB/IH
- GH=BH/3 and GB=2 BH/3 => GB=2GH
- Therefore and EB=2IH, e=2(d+f)/2
- e=d+f