In this page we have *Understanding quadrilaterals class 8 worksheets with Answers*.This worksheet includes Multiple choice question , fill in the blank,True and false, Long answer type questions. Hope you like them and do not forget to like , social share
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Find the number of sides of a regular polygon in which each exterior angle has a measure of 40°$

exterior angle=40°

Interior angle =180 -40=140 °

Let n be the sides, then

Sum of interior angles= $(n-2) \times 180$

$140 n=(n-2) \times 180$

$n=9$

The perimeter of the parallelogram is 38 cm . One of the side is 12 cm, find the other side

In a parallelogram, oppossite sides are equal

Let x be the other side

Then
$2x + 2 \times 12 =38$

$x=7$ cm

Diagonals of the rhombus is 10 cm and 16 cm . What is the area of the rhombus

Area of the rhombus = $ \frac {1}{2} \times d_1 \times d_2$
Where $d_1$ and $d_2$ are the diagonals
Now as per the question

One of the angle in the parallelogram is 50°. Find the other angles in the parallelogram

Adjacent angles are supplementary, So

$x + 50=180$

x=130°

So angles are 50°,130°,50°, 130°

In the below figure, the measure of the angle DBC

In triangle PAB

$\angle APB + 31 + 29=180$

$\angle APB=120^0$

So $\angle BPC= 180 -120=60^0$

In triangle BPC

$\angle DBC + 60 + 34=86^0$

$\angle =

Three angles of a quadrilateral are 50°, 40° and 123°.Find its fourth angle.

Let fourth angle be x. Then $50 + 40 + 123 + x = 360$.

or $x = 360 – 50 – 40 – 123$

$= 360 – 213 = 147$

In the figure, HOPE is a rectangle. Its diagonals meet at G. If HG = 5x + 1 and EG = 4x + 19, find x

Since diagonals of a rectangle bisect each other,

HP = 2HG = 2 (5x + 1) = 10x +2

and OE = 2EG = 2(4x +19) = 8x + 38

Diagonals of a rectangle are equal. So HP = OE

or 10x + 2 = 8x + 38

or 2x = 36 or x = 18

In the given parallelogram YOUR, $\angle RUO = 120^0$ and OY is extended to point S such that $\angle SRY = 50^0$. Find $\angle YSR$

Since in parallelogram, opposite angles are equal

$\angle RYO=120^0$

Then $\angle RYS=180 -120=60^0$

Now in a triangle RYS

$\angle YSR + \angle RYS + \angle YRS=180$

$\angle YSR= 180- 60-50=70^0$

The diagonals of a rhombus are 8 cm and 6 cm. Find its side.

Since diagonals bisect each other and are Perpendicular,Side is given by pythagorus theorem as

$a= \frac {1}{2} \sqrt {d_1^2 + d_2^2} = 5$ cm

Two angles of a quadrilateral are each of measure 75° and the other two angles are equal. What is the measure of these two angles

So $2 \times 75 + 2x=360

$x=105$

(i) Diagonals of a rectangle are __________.

(ii)In an parallegram, adjacents angles are _____

(iii)The sum of all exterior angles of a polygon is __________.

(iv)The measure of each exterior angle of a regular pentagon is __________.

(v) The number of sides of a regular polygon whose each interior angle is of 135° is ___

(i) equal

(ii)equal

(iii) 360°

(iv) 72°

(v) 8

(i) Diagonals of a rectangle are perpendicular to each other

(ii)All angles of a trapezium are equal

(iii)Every square is a trapezium.

(iv)If diagonals of a quadrilateral are equal, it must be a rectangle.

(v) Every square is a rhombus

(vi) ALl parallelograms are kites but all kites are not parallelogram

(i) False

(ii)False

(iii) True

(iv)false

(v) false

(vi) True

The sum of angles of a concave quadrilateral is

(a) more than 360°

(b) less than 360°

(c) equal to 360°

(d) twice of 360°

The sum of adjacent angles of a parallelogram is

(a) 180°

(b) 120°

(c) 360°

(d) 90°

ABCD is a rectangle .F and E are the mid points of BC and CD respectively. If area of the $\Delta BEF=7cm^2$, then the area of the rectangle ABCD is

(a) 49 cm

(b) 42 cm

(c) 56 cm

(d) 28 cm

Length of one of the diagonals of a rectangle whose sides are 24 cm and 7 cm is

(a) 25 cm

(b) 20 cm

(c) 26 cm

(d) 35 cm

Which of the following can never be the measure of exterior angle of a regular polygon?

(a) 30°

(b) 36°

(c) 45°

(d) 22°

ABCD is a parallelogram. Find the value of p

(a) 30°

(b) 100°

(c) 60°

(d) 80°

Find the value of q

(a) 30°

(b) 36°

(c) 45°

(d) 70°

Find the value of r

(a) 30°

(b) 100°

(c) 60°

(d) 80°

13. a

14. a

15. c

16. a

17. d

18. a

19. d

20. d

This Understanding quadrilaterals class 8 worksheets with Answers 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.

**Notes****NCERT Solutions**

Class 8 Maths Class 8 Science