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Understanding Quadrilaterals Class 8 Extra Questions




In this page we have Understanding Quadrilaterals Class 8 Extra Questions . Hope you like them and do not forget to like , social share and comment at the end of the page.
Question 1.
The sum of the interior angles of a regular polygon is twice the sum of the exterior angles. Find the number of sides of the polygon

Answer

Let n be the sides,then (n2)×180=2×360 n=6


Question 2.
Three angles of the quadrilaterals are in the ratio 2:3:4. The sum of the least and the greatest of these three angles is equal to 180°. Find all the angles of the quadrilateral

Answer

Three angles of the quadrilaterals are in the ratio 2:3:4, then it will be 2x,3x,4x.
Now it is given
2x+4x=180
x=30
So three angles are 60°,90°,120°
Let y be the fourth angle,Now in a quadrilateral
Sum of all angles =360
y+60+90+120=360
y=90
So All the four angles are 60°,90°,120°,90°


Question 3.
The exterior angle of a regular polygon is one-fifth of its interior angle. How many sides has the polygon?

Answer

let the interior angle be x,then exterior angle will be (180- x )
Now as per the question
(180x)=15x
Solving this, we get
x= 150°
Therefore,Each interior angle is 150°
Now we know that
Sum of all interior angles is given by =(n2)×180
Therefore
(n2)×180=150n
Simplifying this we get
6n - 5n = 12
n = 12
So, Number of sides= 12


Question 4.
One of the angle in the parallelogram is 80°. Find the other angles in the parallelogram

Answer

Adjacent angles are supplementary, So
x+80=180
x=100° So angles are 80°,100°,80°, 100°


Question 5.
The angles of the quadrilateral is in the ratio 1:2:3:4. Find all the angles

Answer

Let x be common ratio, then angles are 1x,2x,3x,4x
Sum of all angles =360
1x+2x+3x+4x=360
x=36
So angles are 36°, 72°, 108°,144°


Question 6.
One of the diagonals of a rhombus is equal to its sides. Find the measures of all the angles of the rhombus

Answer

Understanding Quadrilaterals Class 8 Extra Questions
Here AB=BC=CD=AD
Also AB=AC
Now in Triangle ABC,
AB=BC=AC
Hence equliateral triangle
B=60, BAC=60 and BCA=60
Now in Triangle ACD
AC=CD=AD
Hence equliateral triangle
D=60, DAC=60 and DCA=60
Now A=BAC+DAC=120
C=BCA+DCA=120
Hence angles are 60°, 120°, 60°,120°


Question 7.
In a parallelogram ABCD, the bisectors of ∠ A and ∠ B meet at O. Find ∠ AOB.


Question 8.
Find the value of x in the trapezium ABCD

Answer

Since DC and AB are parallel , these angles are supplementary
x22+x+42=180
2x+20=180
x=80


Question 9.
The diagonals of a rhombus are 8 cm and 15 cm. Find its side.

Answer

Since diagonals bisect each other and are Perpendicular,Side is given by pythagorus theorem as
a=12d21+d22=8.5 cm



Question 10.
Find the values of x and y in the following parallelogram.

Answer

Oppossite angles are equal
So 6y=120, y=20
Now adjacent angles are supplementary
120+5x+10=180
x=10



Summary

This Understanding Quadrilaterals Class 8 Extra Questions is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feebback on the mail. You can download this also using the below link


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