Points and vectors

1103030704

Level: 
A
We are given points \( A = [2;1] \), \( B = [4;-1] \), and \( T = [6;2] \), where point \( T \) is the centroid of triangle \( ABC \). Find the length of the median of triangle \( ABC \) to side \( AC \).
\( |t_b|=\frac{\sqrt{117}}2 \)
\( |t_b|=\frac{\sqrt{45}}2 \)
\( |t_b|=\frac{\sqrt{153}}2 \)
\( |t_b|=\sqrt{117} \)

1103030701

Level: 
A
We are given points \( A = [1;-1;2] \), \( B = [0;5;-3] \), \( S = [2;0;5] \). Point \( S \) is the centre of a parallelogram \( ABCD \). Find the coordinates of vertices \( C \) and \( D \).
\( C = [3;1;8]; D = [4;-5;13] \)
\( C = [4;-5;13]; D = [3;1;8] \)
\( C = [1;1;3]; D = [2;-5;8] \)
\( C = [-3;-1;-8]; D = [-4;5;-13] \)

1003020901

Level: 
C
Let there be vectors: \(\overrightarrow{a}=(1;3;-1)\), \(\overrightarrow{b}=(0;3;1)\), \(\overrightarrow{c}=(-1;2;2)\). Find \(\overrightarrow{a}\times\overrightarrow{b}\) and \(\left(\overrightarrow{a}\times\overrightarrow{b}\right)\cdot\overrightarrow{c}\).
\(\overrightarrow{a}\times\overrightarrow{b}=(6;-1;3); \left(\overrightarrow{a}\times\overrightarrow{b}\right)\cdot\overrightarrow{c}=-2\)
\(\overrightarrow{a}\times\overrightarrow{b}=8; \left(\overrightarrow{a}\times\overrightarrow{b}\right)\cdot\overrightarrow{c}=(-8,16,16)\)
\(\overrightarrow{a}\times\overrightarrow{b}=(-6;1;-3); \left(\overrightarrow{a}\times\overrightarrow{b}\right)\cdot\overrightarrow{c}=2\)
\(\overrightarrow{a}\times\overrightarrow{b}=\sqrt{46}; \left(\overrightarrow{a}\times\overrightarrow{b}\right)\cdot\overrightarrow{c}=2\)

9000108802

Level: 
B
Given the points \(A = [1;2]\), \(B = [2;6]\) and \(C = [3;-1]\), find the interior angles of the triangle \(ABC\). Round to the nearest degree.
\(22^{\circ }\), \(26^{\circ }\), \(132^{\circ }\)
\(26^{\circ }\), \(45^{\circ }\), \(109^{\circ }\)
\(22^{\circ }\), \(48^{\circ }\), \(110^{\circ }\)
\(17^{\circ }\), \(31^{\circ }\), \(132^{\circ }\)

9000108803

Level: 
B
Consider the vector \(\vec{u} = (\sqrt{3};1)\). Find the vector \(\vec{w}\) such that \(\left |\vec{w}\right | = 4\) and the angle between \(\vec{u}\) and \(\vec{w}\) is \(60^{\circ }\). Find all solutions.
\(\vec{w} = (0;4)\), \(\vec{w} = (2\sqrt{3};-2)\)
\(\vec{w} = (0;-4)\), \(\vec{w} = (\sqrt{7};-3)\)
\(\vec{w} = (0;4)\), \(\vec{w} = (\sqrt{7};3)\)
\(\vec{w} = (\sqrt{5};\sqrt{11})\), \(\vec{w} = (2\sqrt{3};-2)\)