The DAV Class 5 Maths Solutions and **DAV Class 5 Maths Chapter 16 Worksheet 4** Solutions of Triangles offer comprehensive answers to textbook questions.

## DAV Class 5 Maths Ch 16 Worksheet 4 Solutions

Question 1.

Identify the scalene, isosceles, and equilateral triangles.

(a)

Solution:

Isosceles Triangle (Two sides are equal)

(b)

Solution:

Equilateral Triangle (Three sides are equal)

(c)

Solution:

Scalene Triangle (No side are equal)

(d)

Solution:

Isosceles Triangle (Two sides are equal)

(e)

Solution:

Scalene Triangle (All the sides are different)

Question 2.

Identify the acute, obtuse, and right-angled triangles.

(a)

Solution:

Right-angled triangle (One angle is 90°)

(b)

Solution:

Obtuse angled triangle (One angle is obtuse)

(c)

Solution:

Acute angled triangle (all angles are acute)

Question 3.

Find the third angle of this triangle. What type of triangle is this? Why?

Solution:

Let the third angle be x°.

Sum of all the angles of a triangle is 180°.

So, 40° + 50° + x° = 180°

⇒ 90° + x° = 180°

⇒ x° = 180° – 90°

⇒ x° = 90°

As one angle is 90° it is a right triangle.

Question 4.

Sum of two angles of a triangle is 90°. Find the third angle. What type of triangle is this?

Solution:

Sum of two angles = 90°

Let the third angle = x°

x° + sum of two angles = 180° (sum of 3 angles of triangle is 180°)

⇒ x + 90° = 180°

⇒ x° = 180° – 90°

⇒ x° = 90°

As one angle is 90° of a triangle it is a right-angled triangle.

Question 5.

If the measure of one angle of a right-angled triangle is 48°, find the other two angles.

Solution:

As it is right-angled triangle one of the angles is 90°.

Other angle = 48°

Let the third angle be x°

x° + 48° + 90°= 180°

⇒ x° + 138°= 180°

⇒ x° = 180° – 138°

⇒ x° = 42°

So, the other two angles are 90°, 42°.

Question 6.

Fill in the blanks.

(a) A triangle whose any one angle is a right angle, is called a _________ triangle.

Solution:

Right Angled

(b) Each angle of an acute-angled triangle is _________

Solution:

Acute

(c) Anyone angle of an obtuse-angled triangle is _________

Solution:

Obtuse

(d) A triangle whose any two sides are equal in length is called _________ triangle.

Solution:

Isosceles

(e) Sum of three sides of a triangle is equal to _________

Solution:

180°

(f) Sum of lengths of any two sides of a triangle is _________ than the third side.

Solution:

Greater

(g) In an isosceles triangle, any _________ sides are equal in length.

Solution:

Two

**DAV Class 5 Maths Chapter 16 Worksheet 4 Notes**

**Classification of Triangles**

Triangles are classified in two ways-

- According to sides.
- According to angles.

**I. Classification According to Sides**

(a) If all the three sides of a triangle are of different lengths, the triangle is called a scalene triangle

(b) A triangle whose any two sides are of same length is called an isosceles triangle.

(c) A triangle whose all the three sides are of equal length is called an Equilateral triangle.

**II. Classification According to Angles**

(a) A triangle whose all the angles are acute, is called an Acute Angled triangle.

(b) A triangle whose any one angle is a right angle is called a Right Angled triangle.

(c) A triangle whose one angle is obtuse, is called an Obtuse Angled triangle.