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Basic Geometry Theorem

Basic Geometry Theorem

Submitted by alivia on Tue, 2008-09-23 08:14
BASIC PROPORTIONALITY THEOREM

If a line is drawn parallel to one side of a triangle, the other two sides of the triangle are divided proportionally.


Thus, in Fig. DE || BC, According to the above result


AD/DB = AE /EC

We can easily verify this by measuring AD, DB, AE and EC.
We state the converse of the above result as follows :

If a line divides any two sides of a triangle in the same ratio, the line is parallel
to third side of the triangle.

Example:

 if BC is parallel to DE and AB=2, BD=3, AC=4 then what what is AE

Ans: AB/BD=AC/CE =>2/3=4/CE
=>CE =6 and AE = 10

try A tough one


In the above figure angle A is 30 degree and length of BC is 3 cm, then find out the length of

a. DE
b. AB, BD
c. AC, CE
__________________

n/a
Posted on: Fri, 2008-10-31 19:04 #1
pretty fine theorem!!!!!!!

That is pretty clear theorem. But I 'm cofused about the question posted. I could not come up with a solution. Could someone help me out with this.

Thanks in advance.