To find whether or not the angles form a triangle, all you have to do is add all of the angles together. To be a triangle, they must equal exactly 180°.
If all of its angles are the same, it’s an equilateral triangle.
If none of its angles are the same, it’s a scalene triangle.
If 2 of its angles are the same, but one is different, it’s an isosceles triangle.
If it has an angle of 90°, it’s a right triangle.
If all of its angles are less than 90°, it’s an acute triangle.
If it has an angle greater than 90°, it’s an obtuse triangle.
1. 86+53+41= 180
It’s a triangle.
None of the angles are the same, it’s scalene.
The angles are all less than 90°, it’s acute.
2. 47 + 84 + 56 = 187
Not a triangle.
3. 70 + 22 + 68= 160
Not a triangle.
4. 54 + 97 + 29= 180
It’s a triangle.
None of the angles are the same, it’s scalene.
It has an angle greater than 90°, it’s obtuse.
5. 33+ 90 + 57 = 180
It’s a triangle.
None of the angles are the same, it’s scalene.
It has an angle of 90°, it’s a right triangle.
6. 28 + 64 + 100 = 192
Not a triangle.
7. 11 + 101 + 60= 172
Not a triangle.
8. 94 + 35 + 51 = 180
It’s a triangle.
None of the angles are the same, it’s scalene.
It has an angle greater than 90°, it’s obtuse.
9. 52 + 83 + 45 = 180
It’s a triangle.
None of the angles are the same, it’s scalene.
The angles are all less than 90°, it’s acute.
10. 65 + 78 + 37 = 180
It’s a triangle.
None of the angles are the same, it’s scalene.
The angles are all less than 90°, it’s acute.