There are 9 students in a class: 5 boys and 4 girls.
If the teacher picks a group of 4 at random, what is the probability that everyone in the group is a boy?

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

    choose the correct definition for  extremo.  a.  end      b.  extra      c.  extract      d.  eventual 

Given: circle o, cd is diameter, chord ab || cd. arc ab = 74°, find arc ca.