Algebra 2 - Section 13.1 Right Triangle Trigonometry
Learning Target: I can use trigonometric relationships to evaluate trigonometric
functions of acute angles. [G.SRT.6,8]
Review: Pythagorean Theorem
- Used to find a side length of a right triangle.
a2 + b2 = c2
Find the missing side. Give your answer in simplest radical form.
θ
Consider a right triangle:θ (theta) is an acute angle of a right triangle.
sin θ =
cot θ =sec θ =
tan θ =
csc θ =
cos θ =sine cosine tangent
cosecant secant cotangent
Trigonometric ratio - a ratio that compares the lengths of two sides of a right triangle.
The reciprocal trig ratios:
**across from right angle
**NEXT to
1. Find the cos θ
θ6
2√13
4
2. Find the csc θ.
3. Evaluate the 6 trigonometry functions of the angle Ɵ.
θ1612
4. Given the ratio for cos Ɵ, find the remaining ratios.
** make a ∆
Use a calculator to evaluate the trig. function. Round to 4 decimal places.
5. cos 15˚ = 6. sin 15˚ =
8. cot 62˚ =7. csc 18˚ =
To find a missing side using trig.
1. Pick angle.
2. Label sides for THAT angle.
3. Pick trig ratio.
9. y
x
530˚
Find the missing side lengths. Round to the nearest tenth.
y
10.
11. B = 28˚, a = 6
A
B
C
a
b
c
Solve ∆ABC. (means find all angles and sides)
A = ______
b = ______
c = ______
12. A = 45˚, c = √7
B = ______
a = ______
b = ______
Assignment:Right ∆ - Evaluating trig ratio worksheet
Exit problem:Evaluate the 6 trig functions of angle ⩉. 6
8⩉
≈ 2.3 ≈ 2.3;
≈ 16.2; ≈ 8.1