Acute-angle right-triangle ratios
Opposite and adjacent legs depend on the chosen acute angle.
Key knowledge
In a nondegenerate right triangle, sine is opposite leg divided by hypotenuse, cosine is adjacent leg divided by hypotenuse, and tangent is opposite divided by adjacent. Similar triangles give the same ratios for the same acute angle.
Values and equations
sin θ=O/H; cos θ=A/H; tan θ=O/A
- θ
- Chosen acute reference angle rad
- O, A
- Opposite and adjacent leg lengths relative to θ length
- H
- Hypotenuse length length
Conditions and scope
- Choose one acute angle θ; the hypotenuse is opposite the right angle.
- All side lengths are positive and expressed in the same unit; these ratios are dimensionless.
Only nondegenerate right triangles and acute reference angles.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Checked the stated acute-angle right-triangle ratios and restrictions against the listed primary sections; exact inspected boundaries are in the author receipt.
2026-10-10 · Independent Physics and Measurement reference editor (AI editorial bounded review). Independent AI editorial review of this entry's statements, equations, applicability conditions and source coverage. Source checks apply to these claims within their stated limits.
Entry details
Permanent link to this entry ↗- Record identity
- foundation-math-right-triangle-trigonometry
- Revision
- foundations-refresh.1
- Structured reference record
- Foundational reference additions