1.

Find the mirror image of A(-4,2) in (i) the x-axis (ii) the y-axis (iii) the origin Give the name of the figure formed by point A and the points obtained in (i) , (ii) and (iii) above. Also find the distance between poitns A and the point obtained in (iii).

Answer»

Solution :(-4,2) lies in II quadrant i.e, 2 units above the x-axis.
(i) `THEREFORE` image B of a point A(-4,2) in x-axis will be just below the x-axis i.e. in III quadrant. So, image B`=(-4,-2)`.
Since, (-4,2) lies in II quadrant i.e., 4 units left to the y-axis.
`therefore` Image C of a point A(-4,2) in y-axis will be just right to the y-axis i.e, in I quadrant. so, image `C=(4,2)`.
If (x,y) be any point then itsimage in the origin will be `(-x,-y)` i.e., image will be in the opposite quadrant.
Here, (-4,2) lies in II quadrant, so its image D will be in IV quadrant.
`therefore` Image `D= (4,-2)`
Since `AB=CD=2+2=4` units
and `AC=BD=4+4=8` units
`therefore square ACDB` is a RECTANGLE whose LENGTH `AC=8` units and breadth `CD=4` units In right triangle `ACD`.
Now, by Pythagoras theorem `AD^(2)=AC^(2)=CD^(2)`
`=(8)^(2)+(4)^(2)`
`=64+16`
`=80`
`therefore AD =sqrt(80)`units
`rArrAD=4sqrt(5)` units


Discussion

No Comment Found