CTET 2 Math and Science Jul 2019 Paper

∵ Sum of the angles of a triangle = 180°
∴ x + (3x + 20) + 6x = 180°
10x + 20 = 180°
10x = 160°
x = 16°
∴ Angle of triangle are 16°, 68°, 96°
∵ 96° > 16° + 68°
An angle is greater than the sum of other two angle then the triangle is obtuse.