Download To solve any given any triangle (not just a right triangle):

Math 11
Unit 1 summary sheet - Trigonometry
To solve a right-triangle, you can use the SOH CAH TOA (the trigonometry of
right triangles):
opp
hyp
adj
cos  
hyp
opp
tan  
adj
sin  
Remember: you can still use the
Pythagorean Theorem on right triangles:
Hyp
Opp
Hyp2 = Opp2 + Adj2

Adj
To find the area of a triangle when you don’t know its height:
A
1
Use Area  bcSinA
2
c
b
Note: in this situation, you must know two
sides (b and c) and the contained angle (A)
To solve any triangle (not just a right triangle):
A
c
B
b
a
Notice that Angle A and side a
are opposite each other.
C
If you know:
a) Two angles and any side OR
b) Two sides and a non-contained angle
If you know:
a) Three sides OR
b) Two sides and the contained angle
USE the SINE LAW
USE the COSINE LAW
a
b
c


sin A sin B sin C
a 2  b 2  c 2  2bc  cos A
b 2  a 2  c 2  2ac  cos B
c 2  a 2  b 2  2ab  cos C
Solving a triangle means to find all unknown sides and angles