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9th Grade > Mathematics

QUADRILATERALS MCQs

Total Questions : 57 | Page 1 of 6 pages
Question 1. If the ratio of sides (taken in order) of a quadrilateral is a:b:b:a, then it is a 
  1.    kite
  2.    cyclic quadrilateral
  3.    parallelogram
  4.    square
 Discuss Question
Answer: Option A. -> kite
:
A
Here, the ratio is given to be a:b:b:a.
If The Ratio Of Sides (taken In Order) Of A Quadrilateral Is...If KLMJis a quadrilateral, the sides are in the ratio a:b:b:a.
Let KL= a, LM= b, MJ= b and JK= a.
Here, JK and LM are equal and LM and MJ are equal.
We know that,kite is a quadrilateral with two pairs of adjacent sides equal in length.
The data given implies that we have two disjoint pairs of adjacent sides which are equal i.e. there are two pairs of adjacent sides which are equal and the opposite sides are not equal.
This is the very definition of a kite.
Question 2. If ABCD is a parallelogram, then which of the following is true?
  1.    AC=BD
  2.    AB=AC
  3.    ∠A=130∘,∠C=130∘,∠B=50∘
  4.    AB⊥AD
 Discuss Question
Answer: Option C. -> ∠A=130∘,∠C=130∘,∠B=50∘
:
C
If ABCD Is A Parallelogram, Then Which Of The Following Is T...
In a parallelogram, the adjacent sides and anglesare not equal and no sides are perpendicular to other.
A+B=130+50=180
Here, A and B are co-interior angles and their sum is 180.
By the converse of co-interior angles theorem, AD || BC and AB is the transversal.
D+A=50+130=180
Here, D and A are co-interior angles and their sum is 180.
By the converse of co-interior angles theorem, AB ||DC and AD is the transversal.
Question 3. Opposite angles of a parallelogram are equal.
  1.    True
  2.    False
  3.    ∠A=130∘,∠C=130∘,∠B=50∘
  4.    AB⊥AD
 Discuss Question
Answer: Option A. -> True
:
A
Opposite Angles Of A Parallelogram Are Equal.
In the given parallelogram, AD || BC and AB || DC
Consider the diagonal BD which acts as a transversal for BC and AD.
ADB=DBC=x ( alternate angles)
Consider the diagonal BD which acts as a transversal for ABand BC.
ABD=BDC=y ( alternate angles)
We can see that
B=ABD+DBC=x+y
Also,D=ADB+BDC=x+y
Thus, B=D.
Hence, opposite angles of a parallelogram are equal.
Question 4. If one of the angles of a parallelogram is 80°, the other non-adjacent angle is ___degrees.
 Discuss Question

:
In a parallelogram, the opposite angles are equal.Hence, the non-adjacent angle is 80.
Question 5. To determine all angles of a parallelogram, which of the following is the minimum necessary condition?
  1.    Only one angle is known.
  2.    Two angles are known.
  3.    Three angles are known.
  4.    Length of sides should be known
 Discuss Question
Answer: Option A. -> Only one angle is known.
:
A
If one angle of a parallelogram is known, the other angles can be found out by applying the following two properties:
1. The adjacent angles are supplementary.
2. The opposite angles are equal.
Question 6. The three angles of a quadrilateral are 40,80,90. The fourth angle is:
  1.    150∘
  2.    140∘
  3.    180∘
  4.    90∘
 Discuss Question
Answer: Option A. -> 150∘
:
A
According to the angle sum property of a quadrilateral, the sum of all the angles of a quadrilateral is =360
The fourth angle
=360-(40+80+90)
=360210
=150
Question 7. If opposite angles of a parallelogram are supplementary, then the parallelogram is _____ .
  1.    Trapezium
  2.    Rectangle
  3.    Rhombus
  4.    Hexagon
 Discuss Question
Answer: Option B. -> Rectangle
:
B
If Opposite Angles Of A Parallelogram Are Supplementary, The...We know that,
the opposite angles of a parallelogram areequal.
ie. A=CandB=D...(i)
If they are supplementary as well, then
A+C=180
from (i),
A+A=180
2A=180
A=90
Similarly,
C=90
Itmeans that each angle will be equal to 90.
A parallelogram whose internal angles are all 90 is a rectangle.Thus, the figure will be a rectangle.
Question 8. If BDEF And FDCE Are Parallelograms, Then ___  Lies Equidi...
If BDEF and FDCE are parallelograms, then 
___  lies equidistant to points B and C. (Fill in one among A/F/E/D).
 Discuss Question

:
If BDEF And FDCE Are Parallelograms, Then ___  Lies Equidi...
SinceBDEF and FDCE are parallelograms,
BD = FE and DC = FE
Hence, we can see that BD is equal to DC and so, D is the mid-point of BC.
Question 9. Three angles of a quadrilateral measure 37, 130 and 53. Find the measure of the fourth angle.
  1.    40∘
  2.    50∘
  3.    90∘
  4.    140∘
 Discuss Question
Answer: Option D. -> 140∘
:
D
Let the fourthangle be x.
By angle sum property, we know that sum of interior angles of a quadrilateral is 360.
37+130+53+x=360
x=360(37+130+53)=360220=140
Question 10. The sum of external angles of a quadrilateral is equal to the sum of its internal angles.
  1.    True
  2.    False
  3.    90∘
  4.    140∘
 Discuss Question
Answer: Option A. -> True
:
A
The sum of internal angles of a quadrilateral is 360. The sum of external angles of any polygon, irrespective of the number of sides is360. Hence, the given statement is true.

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