| 1. |
Show that the points A(3, 1), B(0, -2), C(1, 1) and D(4, 4) are the vertices of a parallelogram ABCD. |
|
Answer» Step-by-step explanation: Given:-The points A(3, 1), B(0, -2), C(1, 1) and D(4, 4) To show:-Show that the points A(3, 1), B(0, -2), C(1, 1) and D(4, 4) are the vertices of a parallelogram ABCD. Solution:-Method-1:-Given points are A(3, 1), B(0, -2), C(1, 1) and D(4, 4) We know that In a Parallelogram," The diagonals are bisecting to each other" AC and BD are the diagonals =>Mid POINT of AC = Mid Point of BD So To show that the given points are the points of a Parallelogram then we have to show that the mid point of AC is equal to the mid point of BD. Mid point of AC:- Let (x1, Y1)= A(3, 1) =>x1 = 3 and y1 = 1 (x2, y2)=C(1, 1) =>x2 = 1 and y2 = 1 The mid point of the line joining the points (x1 ,y1) and (x2 ,y2) is M(X,y)=[(x1+x2)/2,(y1+y2)/2] =>[(3+1)/2,(1+1)/2] =>(4/2,2/2) =>(2,1) Mid point of AC = (2,1)-----------------(1) Mid Point of BD:- Let (x1, y1)= B(0,-2) =>x1 = 0 and y1 = -2 (x2, y2)=D(4,4) =>x2 = 4 and y2 = 4 The mid point of the line joining the points (x1 ,y1) and (x2 ,y2) is M(x,y)=[(x1+x2)/2,(y1+y2)/2] =>[(0+4)/2,(-2+4)/2] =>(4/2,2/2) =>(2,1) Mid Point of BD = (2,1)---------------(2) From (1)&(2) Mid Point of AC = Mid point of BD Given points A,B,C,D are the vertices of the paralellogram ABCD. Method-2:-Given points are A(3, 1), B(0, -2), C(1, 1) and D(4, 4) To show that the given points are the points of a Parallelogram then we have to show that two pairs of the lengths of the opposite sides of the Parallelogram ABCD. i.e. AB= CD and BC = DA Length of AB :- Let (x1, y1)= A(3, 1) =>x1 = 3 and y1 = 1 Let (x2, y2)= B(0,-2) =>x2= 0 and y2 = -2 We know that The distance between two points ( x1,y1) and (x2, y2) is √[(x2-x1)^2+(y2-y1)^2] AB =√[(0-3)^2-(-2-1)^2] =>AB =√[(-3)^2+(-3)^2] =>AB= √(9+9) =>AB=√18 =>AB=√(2×9) AB=3√2 units ---------(1) Length of BC :- Let (x1, y1)= B(0,-2) =>x1 = 0 and y1 = -2 Let (x2, y2)= C(1,1) =>x2= 1 and y2 = 1 We know that The distance between two points ( x1,y1) and (x2, y2) is √[(x2-x1)^2+(y2-y1)^2] =>BC=√[(1-0)^2+(1-(-2))^2] =>BC=√[1^2+3^2] =>BC=√(1+9) BC =√10 units --------------(2) Length of CD:- Let (x1, y1)= C(1,1)=>x1=1 and y1=1 Let (x2, y2)= D(4,4) =>x2= 4and y2 = 4 We know that The distance between two points ( x1,y1) and (x2, y2) is √[(x2-x1)^2+(y2-y1)^2] =>CD = √[(4-1)^2+(4-1)^2] =>CD=√[3^2+3^2] =>CD=√(9+9) =>CD =√18 =>CD=√(2×9) CD=3√2 units ---------------(3) Length of DA:- Let (x1, y1)= D(4,4) =>x1 = 4 and y1 = 4 Let (x2, y2)= A(3,1) =>x2= 3 and y2 = 1 We know that The distance between two points ( x1,y1) and (x2, y2) is √[(x2-x1)^2+(y2-y1)^2] =>DA =√[(3-4)^2+(1-4)^2] =>DA=√[(-1)^2+(-3)^2] =>DA=√[(-1)^2+(-3)^2] =>DA=√(1+9) DA=√10 units---------------(4) From (1)&(3) AB=BC From (2)&(4) BC=DA Two pairs of opposite sides are equal. Answer:-Given points are the vertices of the paralellogram ABCD. Used Concept:-
Used formulae:-1) The mid point of the line joining the points (x1 ,y1) and (x2 ,y2 ) is M(x,y) =[(x1+x2)/2,(y1+y2)/2] 2)The distance between two points ( x1,y1) and (x2, y2) is √[(x2-x1)^2+(y2-y1)^2] |
|