AP EAMCET · Maths · Three Dimensional Geometry
If the lengths of projections of a line of length \(l\) over the coordinate axes are \(l_1, l_2\) and \(l_3\) respectively, then \(l_1^2+l_2^2+l_3^2\) is equal to
- A \(2 l^2\)
- B \(3 l^2\)
- C \(l^2\)
- D \(5 l^2\)
Answer & Solution
Correct Answer
(C) \(l^2\)
Step-by-step Solution
Detailed explanation
It d be the length of line, then projection on X-axis = dl, projection on Y-axis = dm and projection on Z-axis = dn \(\begin{aligned} & \text { Given, } d=l \text { and } d l=l_1 \\ & \qquad \begin{array}{l}d m=l_2 \\ \text { and } d n=l_3\end{array}\end{aligned}\)…
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