Question

The projections of a line on the co-ordinate axes are 4, 6, 12. The direction cosines of the line are

• A. $\frac{2}{7},\frac{3}{7},\frac{6}{7}$
• B. $2,3,6$
• C. $\frac{2}{11},\frac{3}{11},\frac{6}{11}$
• D. None of these

Answer 1

The correct option is A $\frac{2}{7},\frac{3}{7},\frac{6}{7}$

Direction cosines $=(\frac{4}{\sqrt{16+36+144}},\frac{6}{14},\frac{12}{14})$ or $(\frac{2}{7},\frac{3}{7},\frac{6}{7})$