Questions in 3-d

Select	Question
	If a line makes angles $\alpha ,\beta ,\gamma ,\delta $ with four diagonals of a cube, then the value of ${{\sin }^{2}}\alpha +{{\sin }^{2}}\beta +$ ${{\sin }^{2}}\gamma +{{\sin }^{2}}\delta $ is
	If $\theta $ is the angle between the lines $AB$ and $CD$, then projection of line segment $AB$on line $CD$, is
	The co-ordinates of points $A,B,C,D$are (a, 2, 1), (1, –1, 1), (2, – 3, 4) and (a+1, a+2, a+3) respectively. If $AB=5$and $CD=6$, then $a=$
	If the co-ordinates of the points $A,B,C$be $(-1,\,3,\,2),\,\,(2,\,3,\,5)$ and (3, 5,–2) respectively, then $\angle A=$
	The number of straight lines that are equally inclined to the three dimensional co-ordinate axes, is
	Distance of the point $({{x}_{1}},{{y}_{1}},{{z}_{1}})$ from the line $\frac{x-{{x}_{2}}}{l}=\frac{y-{{y}_{2}}}{m}=\frac{z-{{z}_{2}}}{n}$, where $l,$m and n are the direction cosines of line is
	If the co-ordinates of the points A, B, C, D be (1, 2, 3), (4, 5, 7), (–4, 3, –6) and (2, 9, 2) respectively, then the angle between the lines AB and CD is
	The angle between the lines $\frac{x}{1}=\frac{y}{0}=\frac{z}{-1}$ and $\frac{x}{3}=\frac{y}{4}=\frac{z}{5}$ is
	If $\frac{x-1}{l}=\frac{y-2}{m}=\frac{z+1}{n}$is the equation of the line through (1, 2, –1) and (–1, 0, 1), then (l, m, n) is
	If the angle between the lines whose direction ratios are 2,–1 , 2 and a, 3, 5 be $45{}^\circ $, then a =