The author posted a question in Homework
another challenge? and got a better answer
Response from Дима[+++]
If a line is perpendicular to the plane, it is perpendicular to any line lying in the plane. BC belongs to ABC hence ma is perpendicular to os?
Response from 0[+++]
If a line is perpendicular to the plane it is perpendicular to any line lying in the plane. BC belongs to ABC so it is perpendicular to the plane.
If a line is perpendicular to the plane it is perpendicular to any line lying in the plane. BC belongs to ABC so it is perpendicular to the plane.
Response from 0[+++++]
If MN is perpendicular to ABC then it is also perpendicular to BC, because BC is in the ABC plane
If MN is perpendicular to ABC then it is also perpendicular to BC, because BC is in the ABC plane