x° = 30, 2x° = 60, and 3x° = 90° for the first one. For proof, we can add all 3 angles (x, 2x and 3x) to get 6x, and all angles in a triangle together equals 180° so divide 180° by 6 to get the get the value of x by itself which is 30° So x° = 30, 2x° = 60, and 3x° = 90°
