A circle has a radius of 10 inches. Find the approximate length of the arc intersected by a central angle of \( \frac{2 \pi}{3} \)

2] \( A B C D \) is aparallelogram, \( m(\angle A)+m(\angle C)=200^{\circ} \), then \( m(\angle B)=\ldots(50,80,100,160) \)

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 points lie on more than one of these ten lines? (A) 10 (B) 36 (C) 45 (D) 55 (E) 100

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?

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. \[ [12 \pi \mathrm{~cm} \approx 37,68 \mathrm{~cm} \mathrm{e} 18 \pi \mathrm{~cm} \approx 56,52 \mathrm{cm]} \]