La somma delle lungheaze di due circonferente è di \( 49 \pi \mathrm{~cm} \) e una è \( \frac{3}{4} \) dell'altra. - Calcola Гarea dei due cerchi.

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?

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

6. Teken die volgende hoeke: \( \begin{array}{l}\text { a) } \angle C D E=70^{\circ} \\ \text { b) } \angle K L M=125^{\circ} \\ \text { c) } \angle P Q R=210^{\circ}\end{array} \)

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.