Find the distance of the point `(21,0)` from the plane `2x+y+2z+5=0.`

Options

A. `10/3`
B. `5/3`
C. `10/9`
D. none of these

Answer

A

Explanation

We know that the distance of the point `(x_(1),y_(1),z_(1))` from the plane `ax+by+cz+d=0` is
`(|ax_(1)+by_(1)+cz_(1)+d|)/(sqrt(a^(2)+b^(2)+c^(2))`
So, required distance `=(|2xx2+1+2xx0+5|)/(sqrt(2^(2)+1^(2)+2^(2)))=10/3`