This week, I have learned how to find the missing angle or missing length by using cos law.
There are 2 ways to use the cos law.
- To find the missing angle
- To find the missing lenght
To find the missing angle, we use : cosC=
To find the missing length, we use : cos C
Let’s try an example
We know that angle C is 37, and we are looking for the length C.
Lets write down every thing in the formula.
C= 3.9 cm
Lets try another example.
cos X= 2(6)(5)
X= 2(6)(5) * cos^-1