A perpendicular slope is a slope that is the negative reciprocal of the current slope. Therefore, 3.
-120° = -2π/3 radians.
Tangent is defined as Opposite/Adjacent or Sine/Cosine in a unit circle. So, if you have memorized the unit circle,
sin(-2π/3) = √3/2
cos(-2π/3) = -1/2
So, tan(-2π/3) would be:

Simplify, and you get:

And, so, tan(-2π/3) = -√3
∠R = 100° , ∠S = 40° and ∠T = 40°
<u>Step-by-step explanation:</u>
In a triangle, sum of all the angles in a triangle is equal to 180 degrees.
In Δ RST,
∠R + ∠S + ∠T = 180°
It is given that,
∠S = ∠T
∠R = 2∠S + 20
So plugin these values in the above equation, we will get,
2∠S + 20 + ∠S+ ∠S = 180
4∠S = 180 - 20
∠S = 160/ 4 = 40
∠R = 2× 40 + 20 = 80 + 20 = 100°
∠S = ∠T = 40°
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Answer:
B. sqrt 6 is the answer.maja