Chapter 10 - NCPN

Ongoing Assessment
The angle from the top of a tree to a point 20 meters from the base of
the tree is 52°. What is the height of the tree Round your answer to the
nearest tenth. about 15.6 m
Lesson Assessment
Think and Discuss
1. Which trigonometric ratio in a right triangle relates an angle
measure to the side opposite the angle and the hypotenuse
see margin
2. Explain how to find the height of a tree if the horizontal distance
to the base of the tree and the angle of elevation to the top of
the tree are known.
3. In a right triangle, what ratio of side lengths is equal to the cosine
of an angle
4. What happens to the cosine of an angle if the side lengths of the
triangle are doubled
5. Which trigonometric ratio is the reciprocal of the sine ratio
Practice and Problem Solving
Use triangle DEF to find each trigonometric ratio.
6. sin E 5
13
9. cos E 12
13
12. sec D 13
5
15. csc D 13
12
7. cos D 5
13
10. sin D 12
13
13. csc E 13
5
16. cot E 12
5
8. tan E 5
12
11. tan D 12
5
14. cot D 5
12
17. sec E 13
12
10.1 Right Triangle Trigonometry 439