8. el Angulo llano mide: a. \( 180^{\circ} \) b. \( 90^{\circ} \) c. \( 360^{\circ} \) d. \( 45^{\circ} \) 9. ¿Cuánto suman los angulos internos de cualquier triángulo? a. \( 100 \varrho \) b. \( 160 \varrho \) c. \( 180 \varrho \) d. 900

7a somma dei raggi di due circonferenze misura 15 cm e uno è i \( \frac{2}{3} \) dell'altro. Determina la lunghez- za delle due circonferenze. \[ [12 \pi \mathrm{~cm} \approx 37,68 \mathrm{~cm} \mathrm{e} 18 \pi \mathrm{~cm} \approx 56,52 \mathrm{cm]} \]

3] (a) If the distance between the point \( (a, 7) \) and the point \( (0,-5) \) equals 13 length units find the value of a

50. Ten distinct lines lie in the same plane. No pair of these lines is parallel to each other, and no more than two of the lines intersect at any one point. How many poins lie on more than one of these ten lines? (A) 10 (B) 36 (D) 45 (D) 55 (E) 100

47. The measure, in degrees, of each interior angle of a regular polygon with \( n \) sides is given by \( \frac{(n-2) \mid 80}{n} \). What is the sum of the measures of the interior angles of a regular octagon?

(a) Find the area of the \( \triangle P Q R \). (b) Find \( Q M \). 9. In the given figure \( D L \) and \( B M \) are the heights corresponding to sides \( A B \) and \( A D \) respectively of parallelogram \( A B C D \). If the area of parallelogram is \( 300 \mathrm{~cm}^{2}, A B=30 \mathrm{~cm} \) and \( A D=20 \mathrm{~cm} \). Find the length of \( B M \) and \( D L \).