Question

in which of the following cases the angles

Answer 1

I will answer it...

First of all we know that the sum of all angles[interior] is 180 degree....therefore when we add all the angle....if we get 180 degree then it will form a triangle but if it is not forming then it is not a triangle..

a-90+55+35=180.....yes Option A is the correct answer of question 1

about 17th question...your answer is correct

next 18th question...

we know that the exterior angle is formed by the sum of interior opposite angles...so...

y=35+55=90

x=180-90=90...because of linear pair property...

so the correct answer of 18th question is option D

Answer 2

Q. no. 16

(c) is correct  because sum of its angle is 170 but it ust be 180

Q. no. 17

(b) 45 is correct because 45+45+90=180 is satisfying triangular criteria

Q. no. 18

x+35+55 = 180 {sum of all angles of triangles}

x= 90

and x+y = 180 {Linear pair}

y= 90

hence (d) is correct answer