EASY QUESTION. HELP NEED PLZ. On a smooth plane mirror, if the angle of incidence is 30° then the angle of reflection is

1: 30 degrees

2: 60 degrees

3: 90 degrees

4: none of the above

EXPLAIN YOUR ANSWER.

1: 30 degrees

Step-by-step explanation:

In Physics, we have the law of reflection. This law states that when light rays hit the smooth surface of mirror or any smooth polished surface, the angle of incidence is equivalent to the angle of reflection.

Mathematically:

Angle of incidence = Angle of reflection

From the above question, the angle of incidence is on a smooth plane mirror = 30°

Since:

Angle of incidence = Angle of reflection

30° = 30°

Therefore, based on the law of reflection, the Angle of reflection = 30°

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

x= cost per bracelet

number of bracelets * x + shipping charge = total cost

so

9x+9=72