HEY GUYS...
STATE BASIC PROPORTIONALITY THEOREM....
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《BASIC PROPORTIONAL THEOREM (BPT) 》
Statement:-
If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, the other two sides are divided in the same ratio.
Given:-
A triangle ABC in which a line parallel to side BC intersects other two sides AB and AC at D and E respectively.
To Prove:-
AD/DB = AE/EC.
Construction:-
Let join BE and CD and then draw DM perpendicular to AC and EN perpendicular to AB.
Proof:-
Now, Area of Triangle ADE = 1/2×base×height
1/2×AD×EN
So, ar(ADE) = 1/2×AD×EN
Similarly, ar(BDE) = 1/2×DB×EN
ar(ADE) = 1/2× AE× DM
ar(DEC) = 1/2×EC×DM.
Therefore, ar(ADE)/ar(BDE)
1/2×AD×EN/1/2×DB×EN
then we get AD/DB ----------- (i)
and, ar(ADE)/ar(DEC)
1/2×AE×DM/1/2×EC×DM
then we get AE/EC ------------ (ii)
Triangle BDE and triangle DEC are on the same base DE and between the same parallels BC and DE.
So, ar(BDE) = ar(DEC) -------(iii)
Therefore from equation (i) , (ii) and (iii) we have:-
AB/DB = AE/AC ( HENCE PROVED)
Hope it's helps you mate♡
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Answer:
Basic Proportionality Theorem, also called Thales theorem, states that, " If a straight line is drawn parallel to the third side of a triangle, it divides the other two sides proportionally"
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