Math question if you get this right i will mark you as a brainliest

X=90
A triangle requires a total of 180 degrees, right? The triangle has a straight line coming out of somewhere of course line. A line is 180 degrees meaning the interior angle is 90 degrees and the exterior angle is also 90 degrees sing 90+90=180
Then we can guess that the other angles are 45 degrees each equalling 180 degrees.