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9th Grade > Mathematics

QUADRILATERALS MCQs

Total Questions : 57 | Page 5 of 6 pages
Question 41.


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 42.


Which of the following is a regular quadrilateral?


  1.     Parallelogram
  2.     Square
  3.     Trapezium
  4.     Kite
 Discuss Question
Answer: Option B. -> Square
:
B

A regular quadrilateral is a shape that has four equal sides with all the interior angles equal.
Among the given options, only square has all its four sides  equal with each angle being 90.


Question 43.


Quadrilateral in which only one pair of opposite sides is parallel is known as__


 Discuss Question
Answer: Option B. -> Square
:

Trapezium is a quadrilateral in which only one pair of opposite sides is parallel.


Question 44.


Area of parallelogram is the product of base and corresponding height.


  1.     True
  2.     False
  3.     Three angles are known.
  4.     Length of sides should be known
 Discuss Question
Answer: Option A. -> True
:
A

A parallelogram is made up of two triangles, each having an area equal to the half of the product of base and corresponding height. Adding these two, we find the given statement to be true.


Question 45.


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 46.


If one of the angles of a parallelogram is 80°, the other non-adjacent angle is ___degrees.


 Discuss Question
Answer: Option A. -> Only one angle is known.
:

In a parallelogram, the opposite angles are equal. Hence, the non-adjacent angle is 80.


Question 47.


A diagonal of a parallelogram divides it into two congruent triangles.


  1.     True
  2.     False
  3.     Three angles are known.
  4.     Length of sides should be known
 Discuss Question
Answer: Option A. -> True
:
A

A Diagonal Of A Parallelogram Divides It Into Two Congruent ...
Suppose ABCD is a parallelogram and BD is the diagonal.
There are two triangles - Δ ABD and Δ CDB
In Δ ABD and Δ CDB,
AD = BC   (opposite sides of a parallelogram are equal)
AB = CD   (opposite sides of a parallelogram are equal)
BD is common
By SSS criterion of congruency,
Δ ABD Δ CDB
Hence, the given statement is true.


Question 48.


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.     ABAD
 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 angles are 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 49.


Opposite angles of a parallelogram are equal.


  1.     True
  2.     False
  3.     A=130,C=130,B=50
  4.     ABAD
 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 AB and 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 50.


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 fourth angle 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)=360  220=140


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