What is the mapping rule for a 180 degree rotation about the origin?

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¯¯¯¯¯¯¯¯)?

Jane is cooking beans and rice for dinner tonight. she has 4 cans of black beans, 6 cans of red beans, and 3 cans of garbanzo beans in her cupboard. if she grabs a can of beans without looking at the label, what is the probability of her making black beans and rice for dinner?

A. 120 degrees b. 90 degrees c. 30 degrees d. 60 degrees