8th Grade > Mathematics
UNDERSTANDING QUADRILATERALS MCQs
Total Questions : 464
| Page 3 of 47 pages
:
False
Atrapeziumis a quadrilateral with exactly one pair of parallel sides.
A rhombusis a parallelogram having all sides equal.
:
Let ABCD be a parallelogram, where BE and BF are the perpendicular through the vertex B to the sides DC and AD, respectively.
Let ∠A=∠C=x,∠B=∠D=y [∵ opposite angles are equal in parallelogram]
Now, ∠A+∠B=180∘ [∵ adjacent sides of a parallelogram are supplementary]
⇒x+∠ABF+∠FBE+∠EBC=180∘
⇒x+90∘−x+45∘+90∘−x=180∘
[∵InΔABF,∠ABF=90∘−xandinΔBEC,∠EBC=90∘−x]
⇒−x=180∘−225∘⇒x=45∘∴∠A=∠C=45∘∠B=45∘+45∘+45∘=135∘⇒∠D=135∘
Hence the angles are 45∘,135∘,45∘,135∘.
:
Given, ∠RQY=60∘
∠SRQ=∠RQY [SR∥PY, RQ is the transversal]
⇒∠R=60∘
∴∠S=180∘−∠R=180∘−60∘=120∘ [∵ adjacent angles are supplementary]
Also, SR = 15 cm
⇒ PQ = 15 cm [∵ opposite sides of a parallelogram are equal]
And PS = 11 cm
⇒ QR = 11 cm [∵ opposite sides of a parallelogram are equal]
PR is bisected by SQ, so PR=2×PO=2×6=12cm
:
Kite
In a kite, one diagonal of a the quadrilateral bisects the other.
:
Let the adjacent angles of a parallelogram be x and 5x, respectively.
Then, x+5x=180∘ [∵ adjacent angles of a parallelogram are supplementary]
⇒6x=180∘
⇒x=30∘
∴ The adjacent anlges are 30∘ and 150∘.
Hence, the angles are 30∘,150∘,30∘,150∘ . [∵ opposite angles are equal]
:
Given a quadrilateral PQRS, where
∠P=50∘,∠Q=50∘ and ∠R=60∘
Now, by the angle sum property of a quadrilateral, we have
∠P+∠Q+∠R+∠S=360∘⇒50∘+50∘+60∘+∠S=360∘⇒∠S=360∘−160∘⇒∠S=200∘
One interior angle of the given quadrilateral is greater than 180∘, therefore the quadrilateral is concave.
:
Since, in a rectangle, opposite sides are equal and parallel, so we need the measurement of only two adjacent sides, i.e. length and breadth. Also, each angle measures 90∘.
Hence, we require only two measurements to construct a unique rectangle.
:
Concave polygon
As one interior angle is of greater than 180∘.
:
Yes, ∠MYO=∠RXE
Here, MY and RX are perpendicular to OE.
Since, ∠RXO=90∘⇒∠RXE=90∘ and ∠MYE=90∘⇒∠MYO=90∘.