PEAZIT Aha card
Go straight to resources ↓Sine, cosine and tangent compare sides relative to an angle
For the chosen acute angle, label the opposite leg a, adjacent leg b and hypotenuse c. Sine is a/c, cosine b/c and tangent a/b.
| Relation | Meaning |
|---|---|
| sin α = a/c; cos α = b/c | Sine and cosine have the hypotenuse in the denominator. |
| tan α = a/b | Tangent compares the two legs. |
| a = 3; b = 4; c = 5: sin α = 3/5 | The sine is 0.6. |
One worked example
- sin α = a/c; cos α = b/cSine and cosine have the hypotenuse in the denominator.
- tan α = a/bTangent compares the two legs.
- a = 3; b = 4; c = 5: sin α = 3/5The sine is 0.6.
Watch out: These ratios describe an acute angle in a right triangle. Opposite and adjacent legs swap when you switch angles.
Goal, prerequisites and card origin
What you will learn: Choose the correct right-triangle side ratio.
What you need first: Hypotenuse, legs and fractions.
An original PEAZIT working card. Independent expert review and effectiveness testing have not yet taken place. · v1
Show connections
For the chosen acute angle, label the opposite leg a, adjacent leg b and hypotenuse c. Sine is a/c, cosine b/c and tangent a/b.