1. Show that the points `A(1,2), B(5,4), C(3,8), D(-1,6)` are vertices of a squareSolution:We know that the distance between the two points `(x_1,y_1)` and `(x_2,y_2)` is
`d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)`
A quadrilateral, in which all sides are equal and also the diagonals are equal, is a square.
So, we have to prove all sides `AB=BC=CD=AD` and both diagonals `AC=BD`
The given points are `A(1,2),B(5,4),C(3,8),D(-1,6)`
Length of sides:`AB=sqrt((5-1)^2+(4-2)^2)`
`=sqrt((4)^2+(2)^2)`
`=sqrt(16+4)`
`=sqrt(20)`
`:. AB=2sqrt(5)`
`BC=sqrt((3-5)^2+(8-4)^2)`
`=sqrt((-2)^2+(4)^2)`
`=sqrt(4+16)`
`=sqrt(20)`
`:. BC=2sqrt(5)`
`CD=sqrt((-1-3)^2+(6-8)^2)`
`=sqrt((-4)^2+(-2)^2)`
`=sqrt(16+4)`
`=sqrt(20)`
`:. CD=2sqrt(5)`
`AD=sqrt((-1-1)^2+(6-2)^2)`
`=sqrt((-2)^2+(4)^2)`
`=sqrt(4+16)`
`=sqrt(20)`
`:. AD=2sqrt(5)`
Length of diagonals:`AC=sqrt((3-1)^2+(8-2)^2)`
`=sqrt((2)^2+(6)^2)`
`=sqrt(4+36)`
`=sqrt(40)`
`:. AC=2sqrt(10)`
`BD=sqrt((-1-5)^2+(6-4)^2)`
`=sqrt((-6)^2+(2)^2)`
`=sqrt(36+4)`
`=sqrt(40)`
`:. BD=2sqrt(10)`
Here, all sides `AB=BC=CD=AD`
and both diagonals `AC=BD`
Since, all the sides are equal and both the diagonals are equal
Hence, ABCD is a square
2. Show that the points `A(2,3), B(-2,2), C(-1,-2), D(3,-1)` are vertices of a squareSolution:We know that the distance between the two points `(x_1,y_1)` and `(x_2,y_2)` is
`d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)`
A quadrilateral, in which all sides are equal and also the diagonals are equal, is a square.
So, we have to prove all sides `AB=BC=CD=AD` and both diagonals `AC=BD`
The given points are `A(2,3),B(-2,2),C(-1,-2),D(3,-1)`
Length of sides:`AB=sqrt((-2-2)^2+(2-3)^2)`
`=sqrt((-4)^2+(-1)^2)`
`=sqrt(16+1)`
`=sqrt(17)`
`:. AB=sqrt(17)`
`BC=sqrt((-1+2)^2+(-2-2)^2)`
`=sqrt((1)^2+(-4)^2)`
`=sqrt(1+16)`
`=sqrt(17)`
`:. BC=sqrt(17)`
`CD=sqrt((3+1)^2+(-1+2)^2)`
`=sqrt((4)^2+(1)^2)`
`=sqrt(16+1)`
`=sqrt(17)`
`:. CD=sqrt(17)`
`AD=sqrt((3-2)^2+(-1-3)^2)`
`=sqrt((1)^2+(-4)^2)`
`=sqrt(1+16)`
`=sqrt(17)`
`:. AD=sqrt(17)`
Length of diagonals:`AC=sqrt((-1-2)^2+(-2-3)^2)`
`=sqrt((-3)^2+(-5)^2)`
`=sqrt(9+25)`
`=sqrt(34)`
`:. AC=sqrt(34)`
`BD=sqrt((3+2)^2+(-1-2)^2)`
`=sqrt((5)^2+(-3)^2)`
`=sqrt(25+9)`
`=sqrt(34)`
`:. BD=sqrt(34)`
Here, all sides `AB=BC=CD=AD`
and both diagonals `AC=BD`
Since, all the sides are equal and both the diagonals are equal
Hence, ABCD is a square
3. Show that the points `A(1,7), B(4,2), C(-1,-1), D(-4,4)` are vertices of a squareSolution:We know that the distance between the two points `(x_1,y_1)` and `(x_2,y_2)` is
`d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)`
A quadrilateral, in which all sides are equal and also the diagonals are equal, is a square.
So, we have to prove all sides `AB=BC=CD=AD` and both diagonals `AC=BD`
The given points are `A(1,7),B(4,2),C(-1,-1),D(-4,4)`
Length of sides:`AB=sqrt((4-1)^2+(2-7)^2)`
`=sqrt((3)^2+(-5)^2)`
`=sqrt(9+25)`
`=sqrt(34)`
`:. AB=sqrt(34)`
`BC=sqrt((-1-4)^2+(-1-2)^2)`
`=sqrt((-5)^2+(-3)^2)`
`=sqrt(25+9)`
`=sqrt(34)`
`:. BC=sqrt(34)`
`CD=sqrt((-4+1)^2+(4+1)^2)`
`=sqrt((-3)^2+(5)^2)`
`=sqrt(9+25)`
`=sqrt(34)`
`:. CD=sqrt(34)`
`AD=sqrt((-4-1)^2+(4-7)^2)`
`=sqrt((-5)^2+(-3)^2)`
`=sqrt(25+9)`
`=sqrt(34)`
`:. AD=sqrt(34)`
Length of diagonals:`AC=sqrt((-1-1)^2+(-1-7)^2)`
`=sqrt((-2)^2+(-8)^2)`
`=sqrt(4+64)`
`=sqrt(68)`
`:. AC=2sqrt(17)`
`BD=sqrt((-4-4)^2+(4-2)^2)`
`=sqrt((-8)^2+(2)^2)`
`=sqrt(64+4)`
`=sqrt(68)`
`:. BD=2sqrt(17)`
Here, all sides `AB=BC=CD=AD`
and both diagonals `AC=BD`
Since, all the sides are equal and both the diagonals are equal
Hence, ABCD is a square
4. Show that the points `A(3,2), B(0,5), C(-3,2), D(0,-1)` are vertices of a squareSolution:We know that the distance between the two points `(x_1,y_1)` and `(x_2,y_2)` is
`d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)`
A quadrilateral, in which all sides are equal and also the diagonals are equal, is a square.
So, we have to prove all sides `AB=BC=CD=AD` and both diagonals `AC=BD`
The given points are `A(3,2),B(0,5),C(-3,2),D(0,-1)`
Length of sides:`AB=sqrt((0-3)^2+(5-2)^2)`
`=sqrt((-3)^2+(3)^2)`
`=sqrt(9+9)`
`=sqrt(18)`
`:. AB=3sqrt(2)`
`BC=sqrt((-3-0)^2+(2-5)^2)`
`=sqrt((-3)^2+(-3)^2)`
`=sqrt(9+9)`
`=sqrt(18)`
`:. BC=3sqrt(2)`
`CD=sqrt((0+3)^2+(-1-2)^2)`
`=sqrt((3)^2+(-3)^2)`
`=sqrt(9+9)`
`=sqrt(18)`
`:. CD=3sqrt(2)`
`AD=sqrt((0-3)^2+(-1-2)^2)`
`=sqrt((-3)^2+(-3)^2)`
`=sqrt(9+9)`
`=sqrt(18)`
`:. AD=3sqrt(2)`
Length of diagonals:`AC=sqrt((-3-3)^2+(2-2)^2)`
`=sqrt((-6)^2+(0)^2)`
`=sqrt(36+0)`
`=sqrt(36)`
`:. AC=6`
`BD=sqrt((0-0)^2+(-1-5)^2)`
`=sqrt((0)^2+(-6)^2)`
`=sqrt(0+36)`
`=sqrt(36)`
`:. BD=6`
Here, all sides `AB=BC=CD=AD`
and both diagonals `AC=BD`
Since, all the sides are equal and both the diagonals are equal
Hence, ABCD is a square
5. Show that the points `A(5,6), B(1,5), C(2,1), D(6,2)` are vertices of a squareSolution:We know that the distance between the two points `(x_1,y_1)` and `(x_2,y_2)` is
`d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)`
A quadrilateral, in which all sides are equal and also the diagonals are equal, is a square.
So, we have to prove all sides `AB=BC=CD=AD` and both diagonals `AC=BD`
The given points are `A(5,6),B(1,5),C(2,1),D(6,2)`
Length of sides:`AB=sqrt((1-5)^2+(5-6)^2)`
`=sqrt((-4)^2+(-1)^2)`
`=sqrt(16+1)`
`=sqrt(17)`
`:. AB=sqrt(17)`
`BC=sqrt((2-1)^2+(1-5)^2)`
`=sqrt((1)^2+(-4)^2)`
`=sqrt(1+16)`
`=sqrt(17)`
`:. BC=sqrt(17)`
`CD=sqrt((6-2)^2+(2-1)^2)`
`=sqrt((4)^2+(1)^2)`
`=sqrt(16+1)`
`=sqrt(17)`
`:. CD=sqrt(17)`
`AD=sqrt((6-5)^2+(2-6)^2)`
`=sqrt((1)^2+(-4)^2)`
`=sqrt(1+16)`
`=sqrt(17)`
`:. AD=sqrt(17)`
Length of diagonals:`AC=sqrt((2-5)^2+(1-6)^2)`
`=sqrt((-3)^2+(-5)^2)`
`=sqrt(9+25)`
`=sqrt(34)`
`:. AC=sqrt(34)`
`BD=sqrt((6-1)^2+(2-5)^2)`
`=sqrt((5)^2+(-3)^2)`
`=sqrt(25+9)`
`=sqrt(34)`
`:. BD=sqrt(34)`
Here, all sides `AB=BC=CD=AD`
and both diagonals `AC=BD`
Since, all the sides are equal and both the diagonals are equal
Hence, ABCD is a square
This material is intended as a summary. Use your textbook for detail explanation.
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