El ángulo que forman los vectores \( \bar{a}=(4 ; 1 ;-2) \) y \( \bar{b}(1,-2,-4) \)

555. Длина прямоугольника \( 7 \frac{3}{5} \) см. Его периметр равен периме квадрата со стороной 6 см. Найдите ширину прямоуго ника.

\[ g: \vec{x}=\left(\begin{array}{l}3 \\ 1 \\ 4\end{array}\right)+t\left(\begin{array}{c}2 \\ -7 \\ 5\end{array}\right) \quad h: \vec{x}=\left(\begin{array}{c}5 \\ -6 \\ 9\end{array}\right)+k\left(\begin{array}{l}1 \\ 1 \\ 1\end{array}\right) \] (1) Zeigen Sie, das die Geraden sich schneiden. (2) Geben Sie den Schnittpunkt an. (3) Prüfen Sie, ob sie senkrecht aufeinander stehen. b) Formulieren Sie in mathematischer Schreibweise mithilfe des

WJEC June 2017 Q6 The coordinates of the points \( F \) and \( G \) are \( (8,20) \) and \( (-4,10) \) respectively. (a) Calculate the length of the line FG. Express your answer as a surd in its simplest form, \( n \sqrt{m} \).

Find the equation of the straight line perpendicular to FG that passes through the mid point of \( F G \). Express your answer in the form \( a x+b y+c=0 \), where \( a, b \) and \( c \) are integers. Give your answer in its simplest form.

7. En cada ítem, estudiar la posición relativa entre las dos rectas dadas y graficar ambas en un mismo sistema de coordenadas cartesianas. a) \( \left\{\begin{array}{l}x=1-5 \lambda \\ y=2+3 \lambda \\ z=-5+\lambda\end{array}\left\{\begin{array}{l}x=1 \\ y=1 \\ z=\mu\end{array}(\lambda, \mu \in \mathbb{R})\right.\right. \) b) \( \left\{\begin{array}{l}x=3+2 \alpha \\ y=1-\alpha \\ z=5\end{array}\left\{\begin{array}{l}x=-1-6 \beta \\ y=3+3 \beta \\ z=5\end{array} \quad(\alpha, \beta \in \mathbb{R})\right.\right. \)