15) Trapezoid ABCD has coordinates A(0,9), B(12,9), C(8,4), and D(0,4). Show that AD is not parallel to BC.

Cot(90° − x) = 1 the value of x that satisfies this equation is °. a. 60 b. 135 c. 225 d. 315

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function. a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.

Find the volume of the solid bounded by the plane z=0 and the paraboloid z=1-x^2 –y^2