Prove that a line that divides two sides of a triangle proportionally is parallel to the third side. Be sure to create and name the appropriate geometric figures.

Question

anonymous · Answer

|dw:1397000487880:dw|
for now lets pretend this is your drawing

anonymous · Answer

lol ok well its easier if you look at it from a different perspective so i made a rectangle with  a triangle divided into 3rds

anonymous · Answer

sorry it was way less complicated in my head

anonymous · Answer

is this for your geometry class?

anonymous · Answer

lol i have not learned this yet

anonymous · Answer

@iambatman could you help us out

anonymous · Answer

what im thinking is that if shapes are proportional all the dimensions are proportional as well right?

anonymous · Answer

RANGA THANK GOD CAN YOU HELP ME

ranga · Answer

|dw:1397000930840:dw|

ranga · Answer

If you prove triangles ADE and ABC are similar, then you can prove DE is parallel to BC.

anonymous · Answer

wow our drawings were off lol
i actually did go over this in october

anonymous · Answer

yeah.. Thats what I'm trying to do.. I dont want the answer I wanna try on my own.. well with help. so I have to prove similar angles?

anonymous · Answer

yes

anonymous · Answer

so angle b= angle b by reflective property of equality?

ranga · Answer

If you prove triangles ADE and ABC are similar, then, 
angle ADE = angle ABC and angle AED = angle ACB.
They are corresponding angles and therefore DE is parallel to BC.

anonymous · Answer

sorry what?

ranga · Answer

|dw:1397001477563:dw|

anonymous · Answer

|dw:1397001606596:dw|