P, Q ,R are respectively the mid points of BC, CA and AB of a triangle ABC. PR and BQ meet at X. CR and PQ meet at Y. Prove that XY = 1/4 BC.
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Given : P, Q and R are mid-points in triangle ABC.
To prove : XY = 1 BC / 4
Proof : Since P,Q and R are mid points so
QR || BC => QR || BP
PQ || AB => PQ || BR
Hence, BPQR is parallelogram.
As diagonals of parallelogram bisect each other, so BX = XQ. Hence, X is mid-point on BQ.
Similarily, PCQR is parallelogram.
Hence, Y is mid point on RC.
As, X and Y are midpoints so XY || QR and XY = 1 QR / 2
Moreover, QR || BC ( Q and R are mid-points ). Hence, QR = 1 BC / 2
So, XY = 1/2 ( 1 BC / 2 )
XY = 1 BC / 4
Hence proved!
Have great future ahead!
aaravshrivastwa:
Great answer Bro
Answered by
13
Given
ABC is a Triangle.
P is the m.p of BC
Q is the m.p of CA
R is the m.p of AB
To prove
XY =  BC
Proof
In ΔABC
R is the midpoint of AB.
Q is the midpoint of AC.
∴ By Midpoint Theorem,
RQ║BC
RQ║BP → 1 [Parts of Parallel lines]
RQ =  BC → 2
Since P is the midpoint of BC,
RQ = BP → 3
From 1 and 3,
BPQR is a Parallelogram.
BQ and PR intersect at X
Similarly,
PCQR is a Parallelogram.
PQ and CR intersect at Y.
 X and Y are Midpoints of sides PR and PQ respectively.
In ΔPQR
X is the midpoint of PR
Y is the midpoint of PQ
∴ By Midpoint Theorem,
XY =  RQ
From 3,
XY =  +  BC
XY =  BC
Step-by-step explanation:
I hope it helps you
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