
Right Triangle Trigonometry!!!
-Given a right triangle, there are six trig. ratios which use side lengths and an angle.

(***think back to SOHCAHTOA***)
SIX TRIG. RATIOS: 1. sine, 2. cosine, 3. tangent, 4. secant, 5. cosecant, 6. cotangent
sin ?=opp/hyp —> csc=?hyp/opp cos ?=adj/hyp —> sec ?=hyp/adj tan ?=opp/adj —> cot ?=adj/opp ** <A=?
The opposites are: sin and csc , cos and sec, tan and cot
FIND ALL SIX TRIG. FUNCTIONS:
Example 1:
b=9, a=12, c=15, <A=?
sin ?=12/15=4/5 cos ?=9/15=3/5 tan ?=12/9=4/3
Solving A Triangle:
-Solving a triangle means finding all side lengths and angle measures.
EX 2:
WHEN: <B=63°, a=15
(**act like 63° is ?**) ***make sure your calculator is switched to degree (under mode) in order to solve these problems!!!
1)tan 63°=b/15 –>*15—> 29.440=b
2)180°-90°-63°=<A –>27°=<A 3) (a^2) + (b^2)= (c^2)–> (15^2)+(29.440^2)= c^2 –> 33.040=c
***use common sense knowledge you already know about triangles (1. sohcahtoa , 2. angles=180° , 3. (a^2)+(b^2)=(c^2))
<A=27°, <B=63°, <C=90°, a=15, b=29.440, c=33.040
-There are two special triangles in trig. They are easily found.1. 45° Right Triangles
-Every right triangle with an angle of 45° has the same ratio of sides.
-Both legs are x and the hypotenuse is x?2
EX 3: if the legs are 5, than the hypotenuse= 5?2 EX 4: if the legs are 7?2, than the hypotenuse is 14
EX 5: if the hyp. is ?11, than the legs are ?11/?2
2. 30°-60°-90° Right Triangles
-Every right triangle with the angles 30-60-90 has the same ratio of sides.
*hyp=2x , opp 60°=x?3 , opp 30°=x
EX 1: if the hyp. is 10, than 10/2=5 (opp. 30° angle), 5?3 (opp 60°angle)
EX 2: if the side opp. the 30° angle=8, than the hyp. = 16 (8*2) and the side opp. the 60° degree angle is 8?3
EX 3: if the side opp. the 60° angle= 12, than the side opp. the 30° angle= 12/?3 and the hyp.= 24/?3
*Be able to apply these things to “real life” situations (story problems).
**This looks confusing, but is not that hard…
*HOMEWORK!!!–> pg.772 #5, 6, 8, 9, 15, 16, 22-28, 45, 48, 50