Maths 2 Marks

For a square all sides are equal and each angle is 90°.
∆ABC and ∆ADC are isosceles right−angled triangles.

120°, 30°
Let the third angle be x
Sum of the angles = 180°
120° + 30° + x = 180°
150 + x = 180°
x = 180° – 150°
x = 30°
Third angle = 30°

55°, 85°
Let the third angle be x
Sum of the angles = 180°
55° + 85° + x = 180°
140 + x = 180°
x = 180° – 140°
x = 40°
Third angle = 40°

50°, 90°
Let the third angle be x.
Sum of the angles = 180°
50° + 90° + x = 180°
140 + x = 180°
x = 180° – 140°
x = 40°
Third angle = 40°

80°, 60°
Let the third angle be x
Sum of the angles = 180°
80° + 60° + x = 180°
140 + x = 180°
x = 180° − 140°
x = 40°
Third angle = 40°

75°, 35°
Let the third angle be x
Sum of the angles 180°
75° + 35° + x = 180°
110 + x = 180°
x = 180° – 110°
x = 70°
Third angle = 70°

52°, 68°
Let the third angle be x
Sum of the angles = 180°
52° + 68° + x = 180°
120 + x = 180°
x = 180° – 120°
x = 60°
Third angle = 60°

70°, 60°, 50°
Sum of three angles = 70° + 60° + 50°
= 180°
Yes, A triangle can be formed.
∴ It is an acute-angled triangle.

100°, 50°, 30°
Sum of three angles = 100° + 50° + 30°
= 180°
Yes, A triangle can be formed.
∴ It is an obtuse-angled triangle.

60°, 90°, 90°
Sum of three angles = 60° + 90° + 90°
= 240° ≠ 180°
∴ No, The triangle cannot be formed. ...[∵ one angle is > 90°]

60°, 60°, 60°
Sum of three angles = 60° + 60° + 60° = 180°
Yes, a triangle can be formed.
∴ It is Acute angled triangle. ...[∵ all the angles < 90°]

90°, 55°, 35°
Sum of three angles = 90° + 55° + 55° = 180°
Yes, a triangle can be formed.
∴ It is a Right angled triangle. ...[∵ one angle is 90°]

60°, 40°, 42°
Sum of three angles = 60° + 40° + 42°
= 142° ≠ 180°
No, The triangle cannot be formed.

9 cm, 4 cm, 5 cm.
Sum of two smaller sides = 4 cm + 5 cm
= 9 cm ...(the third side).
∴ No, The triangle cannot be formed.

8 cm, 6 cm, 4 cm
Sum of smaller sides = 6 cm + 4 cm
= 10 cm > 8 cm, third side
∴ Triangle can be formed with these sides
None of the sides is equal.
∴ Yes, it is a scalene triangle