Angle Sum Property of Triangle

Q.

The angles of a triangle are in the ratio $3:4:5.$ Find the smallest angle.

1. ${30}^{\circ }$
2. ${45}^{\circ }$
3. ${60}^{\circ }$
4. ${75}^{\circ }$

Q.

The vertical angle in an isosceles triangle is ${80}^{\circ }$. Find its base angles.

1. ${55}^{\circ }$

2. ${50}^{\circ }$

3. ${75}^{\circ }$

4. ${85}^{\circ }$

Q.

An angle in an isosceles triangle is ${80}^{\circ }$. Find the other two angles corresponding to equal sides.

1. ${40}^{\circ },{60}^{\circ }$

2. ${30}^{\circ },{70}^{\circ }$

3. ${50}^{\circ },{50}^{\circ }$

4. Can't be determined.

Q.

If angles of a triangle are in the ratio $3:4:5$. Find the measure of each angle .

Q. The angles of a triangle are
$(x-40{)}^{\circ },(x-20{)}^{\circ }\text{and}(\frac{x}{2}-10{)}^{\circ }.$
Find the value of x.

1. ${60}^{\circ }$
2. ${75}^{\circ }$
3. ${100}^{\circ }$
4. ${120}^{\circ }$

Q. If the $\angle A,\angle B,$ and $\angle Cof△ABC$ satisfy the relation $\angle B–\angle A=\angle C–\angle B,$ then find the measure of $\angle B.$

1. ${45}^o$
2. ${60}^o$
3. ${90}^o$
4. ${75}^o$

Q.

In an isosceles triangle if the angle at the vertex measures 70 degrees, then what is the measure of base angles?

1. 45 degrees

2. 55 degrees

3. 65 degrees

4. 35 degrees

Q. If the measure of two angles of a triangle are 60° and 30°. Then the measure of the third angle is

1. ${100}^{\circ }$
2. ${90}^{\circ }$
3. ${80}^{\circ }$
4. ${180}^{\circ }$

Q. The measure of two angles of a triangle are 45° and 35°. Find the measure of the third angle.

1. 75°
2. 100°
3. 105°
4. 125°

Q. One angle of a right angled triangle is ${40}^{\circ }$ , then the measure of the other acute angle is

1. ${45}^{\circ }$
2. ${50}^{\circ }$
3. ${65}^{\circ }$
4. ${55}^{\circ }$

Q.

The smallest angle in a triangle with angles in ratio 1:2:3 is

1. 30°

2. 15°

3. 45°

4. 60°

Q. If two angles of a triangle are ${30}^{\circ }$ and ${120}^{\circ }$, then the triangle is a/an _____.

1. right angled triangle

2. scalene triangle

3. equilateral triangle

4. isosceles triangle

Q.

Name the type of triangle: $∆LMNwithm\angle L=30°,m\angle M=70°andm\angle N=80°$.

Q.

The angles in a triangle are in the ratio 1:3:5. The measure of the largest angle is -

1. ${20}^{\circ }$

2. ${40}^{\circ }$

3. ${60}^{\circ }$

4. ${100}^{\circ }$

Q. In a right triangle, if one angle is ${50}^{\circ }$, find its third angle.

1. ${50}^{\circ }$
2. ${40}^{\circ }$
3. ${90}^{\circ }$
4. ${30}^{\circ }$

Q. If two angles of a triangle are 105° and 15°, then the third angle is ____.

1. None of the above
2. 25°
3. 75
4. 60

Q.

Find all the angles of a right angled isosceles triangle. [3 MARKS]

Q. In triangle ABC, $\angle A={70}^{\circ }and\angle B={30}^{\circ }$. Which side of the triangle ABC is the longest?

1. BC
2. AC
3. Cannot be determined
4. AB

Q.

Name the type of triangle: $∆DEFwithm\angle D=90°$.

Q.

Question 3 (e)

Name the following triangle in two different ways: (You may judge the nature of angle by observation)

Q.

Find the value of $\angle ACB$ in the figure shown below:

1. 80${}^{\circ }$

2. 60${}^{\circ }$

3. 40${}^{\circ }$

4. 70${}^{\circ }$

Q.

Two angles of a quadrilateral are 80${}^{\circ }$ and 160${}^{\circ }$. If the remaining two angles are equal, find the remaining angles.

1. 180${}^{\circ }$

2. 120${}^{\circ }$

3. 90${}^{\circ }$

4. 60${}^{\circ }$

Q. A triangle whose two angles measure ${25}^{\circ }$ and ${35}^{\circ }$ is ___ triangle.

1. An obtuse angle

2. An acute angle

3. A right angle

4. An equilateral

Q. In a triangle ABC, $\angle$ ABC + $\angle$ BCA = 120° . Find the value of $\angle$CAB.

1. ${90}^{\circ }$

2. ${180}^{\circ }$

3. ${60}^{\circ }$

4. ${45}^{\circ }$

Q.

In the given triangle PQR , all sides are equal , the measure of each angle is __________

1. ${30}^{\circ }$

2. ${60}^{\circ }$

3. ${90}^{\circ }$

4. ${120}^{\circ }$

Q.

In a $△ABC,\angle A={120}^{\circ },\angle B={40}^{\circ }$ and $\angle C={20}^{\circ }$. What type of triangle is this?

1. Acute Angled Triangle

2. Obtuse Angled Triangle

3. Scalene Triangle

4. Isosceles Triangle

Q.

One angle of a triangle is ${60}^{\circ }$ and the other two angles are in the ratio 2:3. Find the smallest angle in the triangle.

1. ${48}^{\circ }$

2. ${59}^{\circ }$

3. ${61}^{\circ }$

4. ${63}^{\circ }$

Q.

Two angles of a triangle are ${60}^o$ and ${40}^o$. Find its third angle.

1. ${80}^o$

2. ${85}^o$

3. ${70}^o$

4. ${60}^o$

Q.

A triangle has angle measurements of 37°, 76°, and 67°. What type of triangle is this?

1. Obtuse

2. Acute

3. Right angled triangle

4. Isosceles

Q.

If one angle of a triangle is equal to the sum of the other two angles, then the triangle is

1. An isosceles triangle

2. An obtuse triangle

3. An equilateral triangle

4. A right triangle