Question

Please help me..I don’t understand how to solve this question

Answer 1

Answer:

Q3)

i)

Sol-: 100°=x (corresponding angles).

ii)

Sol-: 180°-110°= 70°=x (co-interior angles add up to 180°).

iii)

Sol-: 180°-110°=70°=x

(the linear pair of x will be same as 110, as it's corresponding, and linear pairs add upto 180°).

Q4)

i)

Sol-: (2x+6)+(3x+54)=180°(co-interior angles add upto 180°.

5x+60=180

5x=120(180-60)

x=24

ii)

Sol-:

(2x+15)+(3x+30)= 180

(the linear pair of 2x+15 will be same as 3x+30, as it's corresponding, and linear pairs add upto 180°)

5x+45=180

5x=135 (180-45)

x=27

Answer 2

Answer:

Step-by-step explanation:

Before answering you have to keep in mind that, when there are two parallel lines cut by a transversal there are 3 types of angles formed

1.Corresponding angles (These form in a F shape) (Refer the image titled as corresponding angles to get an idea about how they form)

*Corresponding angles are equal

2. Alternative angles (These form in Z shape) (Refer the image titled alternative angles)

*Alternative angles are also equal

3. Allied angles (These form in a C shape) (Refer img titled as Allied angles)

* Allied angles are not equal.

* Sum of the allied angles is 180

These three angles only form when the two lines are parallel.

4. Vertically opposite angles (Refer the img named Vertically Opposite Angles)

* Vertically opposite angles are equal, even if the two straight lines are not parallel.

5. Remember sum of the angles on a straight line is 180

With this knowledge, now you can start applying them on these questions.

Qs.(i) 100 and x are corresponding angles

Corresponding angles are equal.

So, x = 100

Qs.(ii) x and 110 are allied angles

Sum of the allied angles is 180.

So x + 110 = 180

x = 180 - 110

x = 70

Qs.(iii)See that vertically opposite angle of 110 and x are in C shape. (Allied angles)

Vertically opposite angles are equal. So the allied angle of x is 110

Sum of the allied angles is 180.

So x + 110 = 180

x = 180 - 110

x = 70

In the next two questions, you have to apply your knowledge based on equations too.

Qs. (i) the given angles are allied angles.

Sum of the allied angles is 180.

So,

2x + 6 + 3x + 54 = 180

5x + 60 = 180

To remove 60 we have to subtract it by 60. Whatever we do in one side of the equation, we should also do the same in the other side.

So,

5x + 60 -60 = 180 -60

5x                 = 120

To remove multiplication 5 we have to divide it by 5. Whatever we do in one side of the equation, we should also do the same in the other side.

So,

5x/5 = 120/5

     x =24

I believe based on the knowledge of angles and equation, now you can try out the last question by yourself :)

Hope that you found it useful and can understand.