1. Right Triangles
Unit 4 Vocabulary

2. Acute Angle
An angle whose measure is less than 90 degrees

3. Adjacent Legs
The side leg of a triangle next to the reference angle

4. Cosine
in a right triangle, the ratio of the length of the side adjacent to the angle divided by the hypotenuse

5. Hypotenuse
the longest side of a right triangle; always across from the right angle

6. Opposite Legs
The leg across from the reference angle (never is the hypotenuse).

7. Pythagorean Theorem
In a right triangle, the sum of the squares of the legs (2 shorter sides) is equal to the square of the hypotenuse - which is the longest side.

8. Right Angles
An angle whose measure is equal to 90 degrees

9. Right Triangles
a triangle containing one angle that measures exactly 90 degrees

10. Similar Triangles
triangles with corresponding angles are congruent and corresponding sides are proportional

11. Sine
in a right triangle , the ratio of the length of the side opposite the angle divided by the hypotenuse

12. Special Right Triangles
and triangles

13. Tangent
in a right triangle, the ratio of the length of the side opposite the angle divided by the length of the adjacent side