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Right-Triangle Trigonometry flashcards

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Choose a ratio to recover a sideSine, Cosine, and Tangent
Choose the ratio that connects the two sides you actually have.
When should I use sine and cosine?Sine, Cosine, and Tangent
Identify the correct side ratio for an acute right-triangle angle.
What method supports choose a ratio to recover a side?Sine, Cosine, and Tangent
opposite=hypotenuse·sin θ
TangentSine, Cosine, and Tangent
Tangent compares the legs directly.
Sine and cosineSine, Cosine, and Tangent
Sine uses the far leg; cosine uses the near leg.
What must I check in sine, cosine, and tangent?Sine, Cosine, and Tangent
Define opposite and adjacent relative to the selected acute angle; the hypotenuse is always opposite 90°
What method supports tangent?Sine, Cosine, and Tangent
tan θ=opposite/adjacent
What method supports sine and cosine?Sine, Cosine, and Tangent
sin θ=opposite/hypotenuse; cos θ=adjacent/hypotenuse
When should I use choose a ratio to recover a side?Sine, Cosine, and Tangent
Select sine, cosine, or tangent using the known and requested sides.
When should I use tangent?Sine, Cosine, and Tangent
Use the ratio of the two legs.
Angle recovery and modeFinding Missing Sides and Angles
Inverse trig asks which angle has that ratio.
When should I use missing leg from an exact angle?Finding Missing Sides and Angles
Use an exact trigonometric ratio to find a side.
What method supports angle recovery and mode?Finding Missing Sides and Angles
θ=arctan(opposite/adjacent), 0°<θ<90°
Missing hypotenuseFinding Missing Sides and Angles
The longest side must be larger, so divide by the leg fraction.
Missing leg from an exact angleFinding Missing Sides and Angles
An exact angle can give an exact side multiplier.
What must I check in finding missing sides and angles?Finding Missing Sides and Angles
Use degree mode for degree angles and radian mode for radian angles; inverse-trig angle recovery is a supporting extension
What method supports missing hypotenuse?Finding Missing Sides and Angles
hypotenuse=adjacent/cos θ
What method supports missing leg from an exact angle?Finding Missing Sides and Angles
sin30°=1/2; cos60°=1/2
When should I use angle recovery and mode?Finding Missing Sides and Angles
Use an inverse function or a standard exact ratio to find an angle.
When should I use missing hypotenuse?Finding Missing Sides and Angles
Divide by the known side-to-hypotenuse ratio.
Recover a complementary ratioComplementary Angles and Trigonometric Relationships
Use the complementary relationship before reaching for an inverse calculator.
When should I use complementary acute angles?Complementary Angles and Trigonometric Relationships
Recover the other acute angle in a right triangle.
What method supports recover a complementary ratio?Complementary Angles and Trigonometric Relationships
sin²θ+cos²θ=1; cosβ=sinα when α+β=90°
Cofunction ratiosComplementary Angles and Trigonometric Relationships
Sine of one corner is cosine of the other.
Complementary acute anglesComplementary Angles and Trigonometric Relationships
The two sharp corners split a right angle.
What must I check in complementary angles and trigonometric relationships?Complementary Angles and Trigonometric Relationships
The cofunction identities pair angles summing to 90°; do not confuse them with equal-angle claims
What method supports cofunction ratios?Complementary Angles and Trigonometric Relationships
sin θ=cos(90°−θ)
What method supports complementary acute angles?Complementary Angles and Trigonometric Relationships
α+β=90°
When should I use recover a complementary ratio?Complementary Angles and Trigonometric Relationships
Translate a known ratio to the complementary angle.
When should I use cofunction ratios?Complementary Angles and Trigonometric Relationships
Use a sine-cosine complement identity.
Quadrants and reference anglesDegrees, Radians, and Relevant Unit-Circle Relationships
Find the reference angle and then apply the quadrant signs.
When should I use degree-radian conversion?Degrees, Radians, and Relevant Unit-Circle Relationships
Convert angle measures with π radians equal to 180°.
What method supports quadrants and reference angles?Degrees, Radians, and Relevant Unit-Circle Relationships
cos(180°−α)=−cosα; sin(180°−α)=sinα
Unit-circle coordinatesDegrees, Radians, and Relevant Unit-Circle Relationships
Cosine is left-right; sine is up-down.
Degree-radian conversionDegrees, Radians, and Relevant Unit-Circle Relationships
Use 180° and π radians as equal measures.
What must I check in degrees, radians, and relevant unit-circle relationships?Degrees, Radians, and Relevant Unit-Circle Relationships
A full revolution is 2π radians or 360°; unit-circle coordinates are (cosθ,sinθ) and quadrant signs matter
What method supports unit-circle coordinates?Degrees, Radians, and Relevant Unit-Circle Relationships
(x,y)=(cosθ,sinθ), x²+y²=1
What method supports degree-radian conversion?Degrees, Radians, and Relevant Unit-Circle Relationships
radians=degrees·π/180
When should I use quadrants and reference angles?Degrees, Radians, and Relevant Unit-Circle Relationships
Use a reference angle and signs to find an exact trig value.
When should I use unit-circle coordinates?Degrees, Radians, and Relevant Unit-Circle Relationships
Connect sine and cosine to horizontal and vertical coordinates.
Sloped path and vertical riseTrigonometric Word Problems
A sloped length is the longest side, so choose sine for the rise.
When should I use angle of elevation?Trigonometric Word Problems
Relate vertical rise and horizontal distance with tangent.
What method supports sloped path and vertical rise?Trigonometric Word Problems
vertical rise=sloped length·sinθ
Observer heightTrigonometric Word Problems
The trig triangle starts at eye level, so add that level back.
Angle of elevationTrigonometric Word Problems
Elevation connects height above the sightline to horizontal distance.
What must I check in trigonometric word problems?Trigonometric Word Problems
Assume level ground and vertical objects only when stated; add observer height separately from the triangle’s vertical rise
What method supports observer height?Trigonometric Word Problems
object height=instrument height+d·tanθ
What method supports angle of elevation?Trigonometric Word Problems
rise=horizontal distance·tanθ
When should I use sloped path and vertical rise?Trigonometric Word Problems
Use sine when the known distance is a hypotenuse.
When should I use observer height?Trigonometric Word Problems
Add instrument height after finding the vertical rise.