in the figure PQ parallel to AB, P and Q are the midpoint of AC and BC, AB = 10cm
a) find PQ
b) find ratio of CP : PA And CQ : QB
( please help me solve this problem, i will make you as brainliest )
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In given figure, P is the mid-point of BC and Q is the mid-point of AP. If BQ when produced meets AC at R, Prove that RA=
3
1
CA.
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Solution
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Given A △ABC in which P is the mid-point of BC, Q is the mid-point of BC, Q is the mid-point of AP, such that BQ produced meets AC at R
To prove RA=
3
1
CA
Construction Draw PS||BR, meeting AC at S.
Proof In △BCR, P is the mid-point of BC and PS||BR.
∴ S is the mid−point of CR.
⇒ CS=SR
In △APS, Q is the mid-point of AP and QR||PS.
∴ R is the mid−point of AS
⇒ AR=RS
From (i) and (ii), we get
AR=RS=SC
⇒ AC=AR+RS+SC=3AR
⇒ AR=
3
1
AC=
3
1
CA [Hence proved]
Answer:
We have
( AC AQ )= 93 = 31
( AB AP )= 10.5 3.5 = 31
In ΔAPQ & ΔABC
( AC AQ )=( AB AP)& ∠PAQ=∠BAC
Thus ΔAPQ∼ΔABC by SAS criterion.
Hence ( AC AQ )=( BCPQ ) (by cpst)
⇒ 31=( BC4.5 )
⇒BC=13.5cm.solution