Name each of the following triangles in two different ways: (you may judge the nature of the angle by observation).

(a)


(b)


(c)


(d)


(e)


(f)

(a) Acute-angled and isosceles triangle


As in this figure we can see all angles are less than 90° and it has two equal sides and these are the property of acute angle and isosceles triangle.


(b) Right-angled scalene triangle


As the triangle has one right angle and three unequal sides and these are the property of right-angled and scalene triangle.


(c) Obtuse-angled and isosceles triangle


As we can see one angle is greater than 90° and it has two equal sides and these are the property of obtuse angle and isosceles triangle.


(d) Right-angled and isosceles triangle


As it has one angle of 90° and two equal sides and these are the property of right-angled and isosceles triangle.


(e) Acute-angled and equilateral triangle


As in the figure we can see all angles are less than 90° and it has all equal sides and these are the property of acute angle and equilateral triangle.


(f) Obtuse-angled and scalene triangle


As we can see one angle is greater than 90° and three unequal sides and according to the property of triangles only obtuse-angled and scalene triangle has these property.


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