\( \left\{\begin{array}{r}A B C \text { triángulo escaleno } \\ \overline{A B}=4 x-3 \mathrm{~cm} \\ \overline{A C}=3 x+1 \mathrm{~cm} \\ \overline{B C}=2 x+5 \mathrm{~cm} \\ \text { perímetro }=66 \mathrm{~cm}\end{array}\right. \)

Construct triangle \( P Q R \) such that \( P Q=8.5 \mathrm{~cm}, Q R=65 \mathrm{~cm} \) and \( P R=4.5 \mathrm{~cm} \)-locate the Point which is equidistant from \( P, Q \) and \( R \) Hence draw a circle passing through \( P, Q \) and \( R \). Measure its radius.

Треугольник \( A B C \) вписан в окружность с центром в точке \( O \). Найди \( \angle B A C \), если \( \angle O B C=31^{\circ} \). Ответ дай в градусах.

If the radius of a circle is 5 cm, what is the area of a sector that measures 60 degrees?

4. L'aire d'un trapéze est de \( 135 \mathrm{~m}^{2} \). On sait également que sa hauteur mesure 9 m et que l'une des bases 13 m Quelle est la mesure de l'autré base?

- Individua il vertice \( C \) di un triangolo isoscele di base \( A B \operatorname{con} A(-1 ; 1) \) e \( B(2 ; 0) \), sapendo che l'altezza va ad \( A B \) misura \( \frac{\sqrt{10}}{2} \)