L and m
are two parallel lines intersected by another
pair of parallel Linee P Р
show that ABC S
COA
Answers
Answer:
Given : l∥m
Transversal p intersects l & m at A & C respectively. Bisector of ∠ PAC & ∠ QCA meet at B. And, bisector of ∠ SAC & ∠ RCA meet at D.
To prove : ABCD is a rectangle.
Proof :
We know that a rectangle is a parallelogram with one angle 90
o
.
For l∥m and transversal p
∠PAC=∠ACR
So,
2
1
∠PAC=
2
1
∠ACR
So, ∠BAC=∠ACD
For lines AB and DC with AC as transversal ∠BAC & ∠ACD are alternate angles, and they are equal.
So, AB∥DC.
Similarly, for lines BC & AD, with AC as transversal ∠BAC & ∠ACD are alternate angles, and they are equal.
So, BC∥AD.
Now, In ABCD,
AB∥DC & BC∥AD
As both pair of opposite sides are parallel, ABCD is a parallelogram.
Also, for line l,
∠PAC+∠CAS=180
o
2
1
∠PAC+
2
1
∠CAS=90
o
∠BAC+∠CAD=90
o
∠BAD=90
o
.
So, ABCD is a parallelogram in which one angle is 90
o
.
Hence, ABCD is a rectangle.
solution
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