3. What is the radius of a circle (rounded to the nearest tenth) that has a circumference of 87 cm ? 10.5 13.8 27.7 5.3

\( f(x)=x^{2}-2 x+2 \) centre de symetrie?

Triangles \( \triangle A O B \) and \( \triangle A O C \) have vertices \( A(0,7), B(-1,-2), C(2,-1) \), and \( O(0,0) \). Show that \( m \angle A O B>m \angle A O C \). Select the correct choice below and fill in the answer boxes within your choice. (Type an integer or decimal rounded to the nearest thousandth as needed.) A. Since \( A B=\square \) and \( A C=\square, \overline{A B}>\overline{A C} \), and thus \( m \angle A O B>m \angle A O C \). B. Since \( A B=\square \) and \( A C=\square, \overline{A B}=\overline{A C} \), and thus \( m \angle A O B>m \angle A O C \). C. Since \( A B=\square \) and \( A C=\square, \overline{A B}<\overline{A C} \), and thus \( m \angle A O B>m \angle A O C \).

Halla el centro y el radio de cada una de las siguientes circunferencias y realiza la gráfica. a. \( 2 x^{2}+2 y^{2}+14 x-10 y+35=0 \) b. \( x^{2}+y^{2}-8 x-10 y+40=0 \) c. \( x^{2}+y^{2}+4 x-6 y=5 \) d. \( x^{2}+y^{2}+10 x-6 y-24=0 \) e. \( x^{2}+y^{2}-23 x+35 y+1 / 75=0 \)

Calculez l'aire d'un cercle dont le diamètre est de 10 m.

E Calcula el área aproximada de cada circulo, en cen- timerros cuadrados, a partir de su radio \( r \) o de su diámetro \( d \). \( \begin{array}{ll}277 . r=7 \mathrm{~cm} & \text { 281. } d=18 \mathrm{~cm} \\ 278 . r=8,5 \mathrm{~cm} & 282 . d=21 \mathrm{~cm} \\ 279 . r=19 \mathrm{~cm} & 283 . d=12,5 \mathrm{~cm} \\ 280 . r=0,12 \mathrm{~m} & 284 . d=0,31 \mathrm{~m}\end{array} \)