CLASSIFYING ANGLES WORKSHEET

1. Classify the angles as acute, right, obtuse straight, reflex or full angle :

35°

135°

205°

180°

90°

360°

270°

2. If 4 times the sum of an angle and 5 is 32°, find the type of the angle.

3. If 2 times the sum of 3 times of an angle and 20 is 1024°, find the type of the angle.

4. If the sum of 5 times of an angle and 2 is 1222°, find the type of the angle.

5. If 5 times the difference between an angle and 22 is 440°, find the type of the angle.

6. If 7 times the difference between 3 times of an angle and 5 is 3745°, find the type of the angle.

7. If 2 times the difference between 9 times of angle and 15 is 6450°,  find the type of the angle.

Classify and write the angles as acute, obtuse and right angle.

8.

9.

10.

11. Classify the following angles (acute angle, obtuse angle and right angle)

30°, 45°, 60°, 90°, 120°, 130°, 170°, 75°

12. The angles below 90° and above 0° are called as ________

13. The angles belo 180° awnd above 90° are called as _________

14. _________ angle is formed by combining two consecutive right angles.

15. Which of the following is obtuse angle in triangle ABC ?

a) ∠A    b) ∠B     c)  ∠C    d) none of these

16. Hands of a clock at 2 hours shows _____ angle.

17. Which of the following alphabets has a right angle in it ?

a)  L    b)  K     c)  Z     d) N

18. Can a right-angled triangle have an obtuse angle?

True/False

19. An isosceles triangle can have a right-angled triangle. True/False

1. Answer :

35°  ---> Acute angle

135°  ---> Obtuse angle

205°  ---> Reflex angle

180°  ---> Straight angle

90°  ---> Right angle

360°  ---> Full angle

270°  ---> Reflex angle

2. Answer :

Let a be the required angle.

4(a + 5) = 32

4a + 20 = 32

4a = 12

a = 3

Angle = 3°

Since 3° is less than 90°, the type of the angle is acute angle.

3. Answer :

Let b be the required angle.

2(3b + 20) = 1024

3b + 20 = 512

3b = 498

b = 166

Angle = 166°

Since 166° is greater than 90° but less than 180°, the type of the angle is obtuse angle.

4. Answer :

Let c be the required angle.

5c + 2 = 1222

5c = 1220

c = 244

Angle = 244°

Since 244° is greater than 180° but less than 360°, the type of the angle is reflex angle.

5. Answer :

Let d be the required angle.

5(d - 2) = 440

d - 2 = 88

d = 90

Angle = 90°

Since the angle is exactly 90°, the type of the angle is right angle.

6. Answer :

Let e be the required angle.

7(3e - 5) = 3745

3e - 5 = 535

3e = 540

e = 180

Angle = 180°

Since the angle is exactly 180°, the type of the angle is straight angle.

7. Answer :

Let f be the required angle.

2(9f - 15) = 6450

9f - 15 = 3225

9f = 3240

f = 360

Angle = 360°

Since the angle is exactly 360°, the type of the angle is full angle. 

8. Answer :

The angle measure shown is lesser than 90 degree, then the given angle measure is acute angle.

9. Answer :

The angle measure shown is greater than 90 degree, then the given angle measure is obtuse angle.

10. Answer :

The shown angle measure is exactly 90 degree, then it is right angle.

11. Answer :

30° ==> Acute angle

45° ==> Acute angle

60°==> Acute angle

90° ==> Right angle

120°==> Obtuse angle

130° ==> Obtuse angle

170° ==> Obtuse angle

75° ==> Acute angle

12. Answer :

The angle which is greater than 0 and lesser than 90 degree, it is called acute angle.

13. Answer :

13. The angle which is greater than 90 and lesser than 180 degree, it is called obtuse angle.

14. Answer :

Sum of two right angles = 180 degree

Straight angle is formed by combining two consecutive right angles.

15. Answer :

a) ∠A = acute angle

b) ∠B = acute angle

c)  ∠C = obtuse angle

So, answer is option c.

16. Answer :

The complete angle is 360 degree.

= 360/12

= 30

Angle between two consecutive numbers in the clock is 30 degree.

Angle between 12 and 2 is 60 degree, it is lesser than 90 degree.

Hands of a clock at 2 hours shows acute angle.

17. Answer :

Which of the following alphabets has a right angle in it ?

a)  L    b)  K     c)  Z     d) N

Option a, L creates right angle.

18. Answer :

Can a right-angled triangle have an obtuse angle?

Only one right angle will be there in any triangle, the other angles will be acute angle. So, the result is false.

True/False

19. Answer :

In any isosceles triangle, it can be a right-angled triangle.  So, the answer is true.

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