Question

If the projections of the line segment AB on the yz-plane, zx-plane, xy-plane are $\sqrt{160} , \sqrt{153} , 5$ respectively then the projection of AB on the z-axis is

• A. $\sqrt{12}$
• B. $\sqrt{13}$
• C. 12
• D. 144

Answer 1

Answer: (C)

12

Answer 2

p, q, r - Projections of AB on the coordinate axes $d_1,d_2,d_3$ = Projections of AB on the coordinate planes $d_1^2 = q^2 +r^2 = 160$ $d_2^2 = r^2 + p^2 = 153$ $d_3^2 = p^2 + q^2 = 25$