Special Right Triangles
Reference Angles and Triangles
ASTC
Solving Trig Equations
Reciprocal Functions
1

What do the legs of a 45-45-90 triangle equal?

x

1

What is the reference angle for a 160-degree angle?

20 degrees

1

In which quadrants is sin positive according to ASTC?

Quadrants I and II

1

Solve the following for θ: 9 tan θ = -12. Round your answers to the nearest tenth.

θ = 126.9 degrees, 306.9 degrees

1

Write out the formula for sec θ in terms of opposite, adjacent, and hypotenuse.

sec θ = Hypotenuse / Adjacent

2

What does the long leg of a 30-60-90 triangle equal?

x√3

2

What is the reference angle for a 237-degree angle?

57 degrees

2

In which quadrants is tangent negative according to ASTC?

Quadrants II and IV

2

Solve the following for θ: 3 cos θ - 1 = 0. Round your answers to the nearest tenth.

θ = 70.5 degrees, 289.5 degrees

2

Write out the formula for cot θ in terms of opposite, adjacent, and hypotenuse.

Cot θ = Adjacent /Opposite

3

If one leg of a 45-45-90 triangle equals 4, what are the values of the other leg and the hypotenuse?

Leg = 4

Hypotenuse = 4√2

3

Use a reference triangle to find the value of the following trig function: cos 45 degrees.

√2 / 2

3

For an angle measuring 197 degrees, which trig functions would be negative?

Sine and cosine

3

Solve the following for θ: 9 sin θ + 8 = 0. Round your answers to the nearest tenth.

θ = 242.7 degrees, 297.3 degrees

3

Write out the formula for csc θ in terms of opposite, adjacent, and hypotenuse.

csc θ = Hypotenuse / Opposite

4

If the short leg of a 30-60-90 triangle equals 3, what are the values of the long leg and hypotenuse?

Long Leg = 3√3

Hypotenuse = 6

4

Use a reference triangle to find the value of the following trig function: tan 120 degrees.

-√3

4

Describe the meaning behind the acronym ASTC.

A = All trig functions are positive in quadrant I

S = Sine is positive in quadrant II

T = Tangent is positive in quadrant III

C = Cosine is positive in quadrant IV

4

Solve the following for θ: tan2 θ = 3. Round your answers to the nearest tenth.

θ = 60 degrees, 120 degrees, 240 degrees, 300 degrees

4

Match the following reciprocal trig function to the basic trig functions.

(a) Cot θ

(b) Csc θ

(c) Sec θ

(a) Tan θ

(b) Sin θ

(c) Cos θ

5

If the long leg of a 30-60-90 triangle equals 9, what are the values of the short leg and hypotenuse?

Short Leg = 3√3

Hypotenuse = 6√3

5

Use a reference triangle to find the sine, cosine, and tangent of θ if θ = 315 degrees.

Sin θ = -√2 / 2

Cos θ = √2 / 2

Tan θ = -1

5

Find the values for the other two trig functions using the following information: cos θ = 2/3 and sin θ > 0.

Sin θ = √5 / 3

Tan θ = √5 / 2

5

Solve the following for θ: 9 sin2 θ - 3 = 0. Round your answers to the nearest tenth.

θ = 35.3 degrees, 144.7 degrees, 215.3 degrees, 324.7 degrees

5

Sin θ = 8/17

Cos θ = 15/17

Tan θ = 8/15

Csc θ = 17/8

Sec θ = 17/15

Cot θ = 15/8

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