Question

please give reason ( which angle is this)
​

Answer 1

Here, 2x + 30° + 3x = 180° ( angle sum property)

5x + 30° = 180°

x = $\large\rm { \frac {(180-30)}{5}}$

$\large\boxed{\rm { \therefore x = 30°.}}$

Now, 30° + 3x + a° = 180° (linear pair)

30° + 3(30°) + a = 180°

30 + 90° + a = 180°

120° + a = 180°

a = 60°

now, 2x + b + 2b = 180° ( linear pair)

2(30) + 3b = 180°

60 + 3b = 180°

3b = 120°

$\large\boxed{\rm { \therefore b = 40°. }}$

Answer 2

Step-by-step explanation:

Here, 30°+3x°+2x°=180°---------(Angles in linear pairs.)

therefore, 30°+5x°=180°

i.e. 5x°=180°-30°

= 5x= 150°

therefore x= 150/5

= x= 30°

Now,

2x°+b°+2b°=180°-----------(Angles in linear pairs.)

2×30+3b=180°

i.e.60°+3b=180°

=3b=180-60

= 3b=120°

therefore, b= 120/3

b=40°

Also,

b°+2b°+a°=180°---------(Angles in linear pairs.)

3b°+a°=180°

therefore, 3×40+a°=180°

= 120+a°=180°

a°=180°-120°

therefore, a°=60°