Lines Angles and Triangles - Test Questions-i

Question 1

Question:   Write complement of 42^o, 87^o, 20^o.

Answer:    Angles 48^o, 3^o, 70^o are the complements of the angles 42^o, 87^o, 20^o respectively.

Question 2

Question:   Write the supplement of 108^o, 93^o, 170^o.

Answer:    Angles 72^o, 87^o, 10^o are the supplements of the angles 108^o, 93^o, 170^o respectively.

Question 3

Question:  

Answer:   
2x+112=360
2x=360-112=248

Question 4

Question:   In the adjoining figure, OA and OB are opposite rays.

(i) If x=75^o, what is the value of y?
(ii) If y=110^o, what is the value of x?

Answer:    (i) If x=75^o then
x+y=180^o ( Linear pair)
75^o+y=180^o
y=180^o-75^o
y=105^o
(ii) If y=110^o, then
x+y=180^o ( Linear pair)
x+110^o=180^o
x=180^o-110^o
x=70^o

Question 5

Question:  
Determine the value of x.

Answer:    4x+2x=180^o ( Linear pair)
6x=180^o

x = 30^o
4x = 4 x 30^o
= 120^o
2x = 2 x 30^o
= 60^o

Question 6

Question:   In the given figure, form a linear pair. If a - b = 80^o, find the values of 'a' and 'b'.

Answer:   

Adding (i) and (ii),
a + b + a - b = 180⁰ + 80⁰
2a = 260^o
a = 130^o
Substituting a = 130^o in (i)
a + b = 180^o
130 + b = 180^o
b = 180^o - 130^o
b = 50^o
a = 130^o and b = 50^o

Question 7

Question:  

Answer:   

Question 8

Question:  

Answer:   

Question 9

Question:  

Answer:    ( straight angle)


Divide both sides by 2,

Question 10

Question:  

Answer:    ...(i) ( they form a linear pair)
...(ii) ( Linear pair)
Equating (i) and (ii),