Types of Quadrilaterals Video Lecture | Mathematics (Maths) Class 8

0:0:0: in this video we will help you to
0:0:2: identify the type of quadrilateral each
0:0:5: one of the following pictures is
0:0:8: ready let's
0:0:10: start as you see the photos observe that
0:0:14: each one has a different shape and
0:0:16: therefore have different
0:0:18: properties the different types of
0:0:20: quadrilaterals are trapezium kite and
0:0:25: parallelogram we are also about to see
0:0:27: the elements of a parallelogram and
0:0:30: types of parallelograms including
0:0:32: rhombus rectangle and square first let's
0:0:36: start by understanding a
0:0:39: quadrilateral a quadrilateral is a
0:0:41: closed shape and a type of polygon that
0:0:44: has four sides four vertices and four
0:0:47: angles so if you see the picture of the
0:0:51: popcorn bucket it has four sides and
0:0:54: hence is a
0:0:55: quadrilateral this type of quadrilateral
0:0:58: is called a trapezium
0:1:0: its property is that only one pair of
0:1:3: opposite lines are
0:1:5: parallel let's observe the second
0:1:7: picture that is a kite and surprisingly
0:1:11: this type of quadrilateral is also
0:1:13: called a kite its properties
0:1:16: include two pairs of adjacent or
0:1:19: neighboring sides are
0:1:21: equal one pair of opposite angles the
0:1:25: ones between the unequal sides are
0:1:28: equal one diagonal bisects the other
0:1:32: which means the longer diagonal divides
0:1:34: the shorter into equal
0:1:37: halves lastly diagonals intersect at
0:1:40: right
0:1:41: angles take a look at the next picture
0:1:45: this type of quadrilateral is called a
0:1:47: parallelogram which is the most
0:1:49: important type of
0:1:51: quadrilateral its properties are
0:1:54: opposite sides are parallel and also are
0:1:56: of equal
0:1:58: length opposite Ang angles are
0:2:1: equal the diagonals bisect each other
0:2:5: adjacent angles are supplementary which
0:2:7: means they are to make
0:2:10: 180° did you know parallelogram is also
0:2:15: called the parent of some other
0:2:17: quadrilaterals as they are obtained by
0:2:19: adding restrictions to the properties of
0:2:23: parallelogram now let's dive deeper into
0:2:28: parallelograms elements of
0:2:31: parallelograms let us Mark the vertices
0:2:33: a b c and d first is the opposite sides
0:2:38: we have two pairs of opposite sides AB b
0:2:42: d c and a d b c next is the opposite
0:2:47: angles can you guess which ones are the
0:2:49: opposite
0:2:51: angles yes you're right we have two
0:2:55: pairs of this as well angle a angle C
0:2:58: and angle B angle D now comes the
0:3:3: adjacent
0:3:4: signs come on let's guess
0:3:8: again
0:3:9: yes yeah we have four pairs of them a b
0:3:14: b c b c c d c d d a and da a
0:3:20: Ab lastly the adjacent
0:3:23: angles again we have four pairs of them
0:3:27: angle a angle B angle B angle c angle c
0:3:32: angle D and angle D angle
0:3:35: a let's try a question given the
0:3:38: parallelogram pqr is with PQ equal to 12
0:3:42: CM and QR equal to 7
0:3:46: cm find the perimeter of the
0:3:50: parallelogram I hope you tried the
0:3:52: question on your
0:3:53: own so to find out the perimeter of the
0:3:57: parallelogram we need the length of of
0:3:59: all the sides to find out the lengths of
0:4:3: the two unknown sides we are going to
0:4:5: use one of the properties of
0:4:7: parallelogram which says that the
0:4:9: opposite sides of parallelogram are
0:4:12: always equal in
0:4:14: length so using this we find that PQ is
0:4:18: equal to Sr is equal to 12 CM and QR is
0:4:22: equal to PS is equal to 7
0:4:25: cm now to calculate the perimeter we add
0:4:29: length p q QR RS SP = to 12 + 7 + 12 + 7
0:4:36: giving us the answer 38
0:4:40: CM next we are going to study more about
0:4:43: angles of
0:4:45: parallelogram notice these two angles
0:4:48: what do you think are they
0:4:50: equal yes they are
0:4:53: equal so here we learned that the
0:4:56: opposite angles of a parallelogram are
0:4:59: all always
0:5:0: equal let's change the angles what
0:5:3: special property do you think these two
0:5:5: angles have let me help you now can you
0:5:10: see these two angles add up to make
0:5:14: 180° that means they are
0:5:17: supplementary let's try a new question
0:5:19: to better understand this concept given
0:5:22: that m8h is a parallelogram angle m is
0:5:26: equal to
0:5:28: 100° find x y and Zed try it on your
0:5:34: own let me give you a hint this question
0:5:37: uses two properties related to
0:5:40: angles so to find X we use the property
0:5:44: that says opposite angles of
0:5:46: parallelogram are always equal hence X
0:5:50: is equal to angle m is equal to
0:5:54: 100° now to find Y and Zed we will use
0:5:58: the second property of angles that says
0:6:1: adjacent angles of parallelogram are
0:6:4: supplementary hence x + y is equal to
0:6:10: 180° X is equal to 100° so taking X on
0:6:15: the other side we get 180 - 100 = to
0:6:21: 80° lastly to find Zed we see that Y and
0:6:25: Zed are angles on a straight line so y +
0:6:29: said is also equal to
0:6:32: 180° hence we get said equal to
0:6:37: 100° just like the angles diagonals of
0:6:41: parallelograms also have some special
0:6:44: properties diagonals are quite amazing
0:6:47: if we see them
0:6:49: closely diagonals of a parallelogram
0:6:52: always BCT each other at the point they
0:6:55: intersect which means they divide each
0:6:57: other in halves at the point point of
0:7:0: intersection just as we said
0:7:2: parallelogram is called the parent of
0:7:5: some other quadrilaterals now we will
0:7:7: see the special
0:7:9: parallelograms first is Rhombus it is a
0:7:12: special parallelogram with all the sides
0:7:16: equal the diagonals even BCT each other
0:7:19: at right
0:7:21: angles second we have a rectangle it
0:7:24: also poses all the properties of a
0:7:26: parallelogram with the Restriction of
0:7:29: all the angles being 90° also the
0:7:32: diagonals are equal and bisect each
0:7:35: other lastly we have a square it has the
0:7:39: restrictions of all the sides being
0:7:41: equal in length diagonals being equal
0:7:44: and also all the angles equal to
0:7:48: 90° we hope that you have understood the
0:7:50: concept of different types of
0:7:53: quadrilateral now here's a secret on how
0:7:56: you can study effectively with the edur
0:7:59: app you can learn with chapter notes
0:8:2: watch video lectures and solve McQ tests
0:8:6: of this chapter on
0:8:8: urv and that's not all you also get
0:8:11: amazing courses for Class 8 and much
0:8:14: more for your class eight
0:8:16: preparation thank you