<u>Answer-</u>
<em>In </em><em>picture 4</em><em>, the triangle is reflected over x axis.</em>
<u>Solution-</u>
While reflecting a point over x axis, (x, y) → (x, -y) rule is followed.
Only the sign of y-coordinate is changed, keeping x-coordinate intact.
In the first picture, though the image is reflected, but it is reflected over y axis.
In the second picture, the image is first reflected over y axis, then it is translated 1 unit down.
We rotating a point 90° clockwise, (x, y) → (y. -x) rule is followed.
In the third picture, the triangle is rotated 90° clockwise and then translated 1 unit to right.
But, in case of the fourth picture, the figure is reflected over x axis. Only the y coordinates sign are changed, all the x coordinates are same as before.