Classification of Triangles Based on Sides

Q. All equilateral triangle are isosceles, but all isosceles triangle are not equilateral. Justify the statement.

Q.

All equilateral triangles are

1. right angled

2. scalene

3. isosceles

4. isosceles right angled

Q. Does the altitude of a triangle drawn from a vertex to the opposite side, bisects the side .

Q.

The ratio of the measure of the vertex angle is to the base angle of an isosceles triangle is $8:5$. Find the measure do the vertex angle?

Q.

Can a triangle have each angle greater than ${60}^{°}$ ?

Q.

Observe the given figure and identify the type of triangle

1. Acute angled triangle

2. Obtuse angled triangle

3. Right triangle

4. Isosceles triangle

Q.

Question 7

Draw five triangles and measure their sides. Check in each case, if the sum of the lengths of any two sides is always greater than the third side.

Q.

In an isosceles triangle, what is the meaning of isosceles and which two words is it made up of?

Q. What is the difference between equalateral and isosceles triangles

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Q. One angle of a linear pair is twice the other. What is the value of the smaller angle?

1. ${50}^{\circ }$
2. ${120}^{\circ }$
3. ${60}^{\circ }$
4. ${40}^{\circ }$

Q.

In the given figure, x = ___

1. ${12}^{\circ }$

2. ${10}^{\circ }$

3. ${15}^{\circ }$

4. ${20}^{\circ }$

Q.

Question 1 (a)

Name the type of the following triangle:

Triangle with lengths of sides 7 cm, 8 cm and 9 cm.

Q. Observe the figure below and write the type of the triangle based on its angle.

Q.

Question 2(d)

Copy the triangle of the following figure on a squared paper. Draw the line(s) of symmetry, if any and identify the type of triangle. (Some of you may like to trace the figures and try paper-folding first! )

Q.

In an equilateral triangle, each angle is of measure _____________.

Q.

The given triangle is a scalene triangle.

1. False

2. True

Q.

Triangle with lengths of sides as 7 , 8, and 9 cms is ______ triangle.

1. Scalene

2. Equilateral

Q.

In the figure shown, if $BE\parallel DCand\angle EBD=\angle EBA$, then BD = ___.

Q.

The angles of a triangle are $x^o,x^o,2x^o$. Find x.

1. ${65}^{\circ }$

2. ${75}^{\circ }$

3. ${45}^{\circ }$

4. ${35}^{\circ }$

Q.

In the given figure, z =___.

1. 110°

2. 45°

3. None of these

4. 40°

Q.

For an isosceles $\Delta NVY$, in which NV = NY, which of the following is true ?

1. $\angle YNV=\angle YVN$

2. $\angle NVY=\angle VYN$

3. $\angle VYN=\angle YNV$

4. None of the above

Q.

In the adjoining figure $△$ ADC is an isosceles triangle

1. True

2. False

Q. Prove the following :
$\left|\begin{array}{cccc}0& x& y& z\\ -x& 0& c& b\\ -y& -c& 0& a\\ -z& -b& -a& 0\end{array}\right|={(ax-by+cz)}^2.$

Q.

The measures of two angles of a triangle are given. Find the measure of the third angle.

$85°$$,45°$

Q.

Is it possible for a $△$PQR that $\angle P=120°,\angle Q=100°and\angle R=40°$? Why?

Q.

The measures of two angles of a triangle are given. Find the measure of the third angle.

$55°$$,65°$

Q.

In an isosceles triangle, if the vertex angle is twice the sum of the base angles, then the angles of the triangle are

1. 90^o, 45^o, 45^o

2. 120^o, 30^o, 30^o

3. 60^o, 60^o, 60^o

4. 80^o, 50^o, 50^o

Q. $\angle AOB$ is a/an _______angle.

1. acute
2. right
3. obtuse
4. none

Q. The measures of the angles of a triangle are $2x,x+25$ and $3x+5$. Find $x$ and then show that the triangle is isosceles.

1. $25$
2. $15$
3. $28$
4. $12$

Q. From the given figure, find the value of x.