If triangle DEF is an isosceles triangle, angle d is the vertex angle, DE = 4x-7, EF = 3x+2 and DF = 6x- 15, find the value of x and the measure of each side

Which expression converts 45 degree to radians

The graph below shows the height of a projectile t seconds after it is launched. if acceleration due to gravity is -16 ft/s2, which equation models the height of the projectile correctly?

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.