can you guys stop please?
It is 59m - not 49.
perimeter of trapezoid: a + b + c + d
12m + 10m + 16m + 21m = 59m - the perimeter of the trapezoid
75 degrees + (the angle next to the 75 degrees) = 180° -> the angle next to the degrees = 105°, so x must also be 105°