C is a circle with radius r. Which of the following is true? Select all that apply

A. The diameter of C is 2r

B. the circumference of C is pi*r

C: the circumference of C is 2pi*r

D. One quarter of the circle has length (pi*r)/4

E. One quarter of the circle has length(pi*r)/2

Need ! give step by step solutions on how to solve number one \frac{9-2\sqrt{3} }{12+\sqrt{3} } number two x+4=\sqrt{13x-20} number three (domain and range) f(x)=2\sqrt[3]{x} +1

One of the same side angles of two parallel lines is 20° smaller than the other one. find the measures of these two angles.

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14