NCERT Solutions Class 6th Maths Chapter – 5 Understanding Elementary Shapes Exercise – 5.6

Question 1. Name the types of following triangles-

(а) Triangle with lengths of sides 7 cm, 8 cm and 9 cm.
(b) ∆ABC with AB = 8.7 cm, AC = 7 cm and BC = 6 cm.
(c) ∆PQR such that PQ = QR = PR = 5 cm.
(d) ∆DEF with m ∠D = 90°.
(e) ∆XYZ with m ∠Y = 90° and XY = YZ.
(f) ∆LMN with m ∠L = 30° m ∠M = 70° and m ∠N = 80°.

Solution –

(a) Scalene triangle
(b) Scalene triangle
(c) Equilateral triangle
(d) Right angled triangle
(e) Right angled isosceles triangle
(f) Acute-angled triangle

Question 2. Match the following-

Solution –

(i) ↔ (e)
(ii) ↔ (g)
(iii) ↔ (a)
(iv) ↔ (f)
(v) ↔ (d)
(vi) ↔ (c)
(vii) ↔ (b)

Question 3. Name each of the following triangles in two different ways- (You may judge the nature of the angle by observation)

Solution –

(i) Acute angled and isosceles triangle
(ii) Right angled and scalene triangle
(iii) Obtuse angled and isosceles triangle
(iv) Right angled and isosceles triangle
(v) Equilateral and acute angled triangle
(vi) Obtuse angled and scalene triangle

Question 4. Try to construct triangles using match sticks. Some are shown here. Can you make a triangle with-

(a) 3 matchsticks?
(b) 4 matchsticks?
(c) 5 matchsticks?
(d) 6 matchsticks?

(Remember you have to use all the available matchsticks in each case)
Name the type of triangle in each case.
If you cannot make a triangle, think of reasons for it.

Solution –

(a) Yes, we can make an equilateral triangle with 3 matchsticks.

(b) No, we cannot make a triangle with 4 matchsticks.

(c) Yes, we can make an isosceles triangle with five matchsticks.

(d) Yes, we can make an equilateral triangle with 6 matchsticks.