According to this diagram , what is cos 23 degrees

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

The function y= x - 4x+ 5 approximates the height, y, of a bird, and its horizontal distance, x, as it flies from one fence post to another. all distances are in feet. complete the square to find and interpret the extreme value (vertex). select two answers: one extreme value and one interpretation.

What is the measure of ba (the minor arc) in the diagram below?