Reflect point a(5, 7, 2) across the xz-plane. where will the new point be located? (-5, -7, 2) (-5, -7, -2) (-5, 7, -2) (5, -7, 2)

When the point (x, y, z) is reflected along the plane, only the coordinates of that particular plane changes (become opposite in sign) and the coordinate of 3rd coordinate remain the same.

In this case, the point A (5,7,2) is reflected along xz plane. So x and z coordinates will be opposite in signs after reflection and y coordinate will not be changed.

So after reflection along xz plane, the new point will be (-5, 7, -2). Thus 3rd option is the correct answer 

The correct answer is $90