Bill says that (x+y)^2 =x ^2+y ^2 is a shortcut rule of multiplication. show the correct answer by giving at least two different explanations (numeric, geometric, etc.) to support your conclusion.

If 90° < θ < 180° and cotθ = -1/3, then cscθ =

How can we find the measure of an exterior angle if we know the measurement of an interior angle

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¯¯¯¯¯¯¯¯)?