Explanation:
We know that,
Magnitude of a unit vector is 1.
and, magnitude of a vector in the form [tex] \sf a \hat{i}+b \hat{j} + c \hat{k} [/tex]
is [tex] \sf \sqrt{a^2+b^2+c^2 } [/tex]
The given vector is,
[tex]\sf \vec{A}= 0.3 \hat{i} + 0.4 \hat{j} + B \hat{k}[/tex]
Magnitude of the given vector is,
[tex]\sf | \vec{A}|= \sqrt{(0.3)^2+(0.4)^2+B^2} =1[/tex]
[tex]\sf \sqrt{0.09+0.16+B^2}=1[/tex]
[tex]\sf 0.25+B^2=1[/tex]
[tex]\sf B^2=1-0.25=0.75[/tex]
[tex]\sf B = \sqrt{0.75} ≈ 0.87[/tex]
