Find equation of straight line through \( (-1,4) \) and perpendicular to the line passing through \( (3,0) \) and \( (1,-2) \).

[b] If \( b \) is the middle proportional between \( a \) and \( c \) , then prove that : \( \frac{a-b}{a-c}=\frac{b}{b+c} \)

In the opposite figure : \( \frac{\mathrm{BE}}{\mathrm{BC}}= \) \( \begin{array}{ll}\text { (a) } \frac{1}{2} & \text { (b) } 2 \\ \text { (c) } \frac{1}{3} & \text { (d) } 3\end{array} \)

Cos'è un cerchio?

the area of \( \triangle A B C=12 \mathrm{~cm}^{2} \), then \( \left(b^{2}+c^{2}-a^{2}\right) \tan A=\cdots \) 12 (b) 24

\( A B C \) est un triangle et \( I \) milieu de \( [B C] \). 1) Soit \( \operatorname{Ebar}\{(A, 1) ;(B, 2) \),\( \} et F b a r\{(B, 2) ;,(C, 1)\} \). a) Montrer que: \( \overrightarrow{A E}=\frac{2}{3} \overrightarrow{A B} \). b) Montrer que: \( \overrightarrow{B F}=\frac{1}{3} \overrightarrow{B C} \) c) Construire les points \( I, E \) et \( F \). 2) Soit \( G b a r\{(A, 1) ;(B, 2) ;,(C, 1)\} \). a) Montrer que \( \operatorname{Gbar}\{(A, 1) ;(F, 3) \),\( \} . \) b) Montrer que \( G \in(E C) \). c) Montrer que \( G \in(I B) \) et construire \( G \). 3) Determiner l'ensemble des points \( M \) du plan qui verifient chacune des équations suivantes: a) \( \|\overrightarrow{M A}+2 \overrightarrow{M B}+\overrightarrow{M C}\|=8 \) b) \( \|\overrightarrow{M A}+2 \overrightarrow{M B}\|=\|\overrightarrow{M C}+2 \overrightarrow{M B}\| \)