Find the measure of the acute or right angle formed by intersecting lines so that c can be mapped to c’ using two reflections. the rotation (x, y) (-x,-y) maps c to c’

Many newspapers carry a certain puzzle in which the reader must unscramble letters to form words. how many ways can the letters of emdangl be arranged? identify the correct unscrambling, then determine the probability of getting that result by randomly selecting one arrangement of the given letters.