What is law of cosines
Answers
Answer:
Step-by-step explanation:
For any triangle:
triangle angles A,B,C and sides a,b,c
a, b and c are sides.
C is the angle opposite side c
The Law of Cosines (also called the Cosine Rule) says:
c2 = a2 + b2 − 2ab cos(C)
It helps us solve some triangles. Let's see how to use it.
Example: How long is side "c" ... ?
trig cos rule example
We know angle C = 37º, and sides a = 8 and b = 11
The Law of Cosines says: c2 = a2 + b2 − 2ab cos(C)
Put in the values we know: c2 = 82 + 112 − 2 × 8 × 11 × cos(37º)
Do some calculations: c2 = 64 + 121 − 176 × 0.798…
More calculations: c2 = 44.44...
Take the square root: c = √44.44 = 6.67 to 2 decimal places
Answer: c = 6.67
Answer:
c2 = a2 + b2 − 2ab cos(C)
Step-by-step explanation:
For any triangle:
triangle angles A,B,C and sides a,b,c
a, b and c are sides.
C is the angle opposite side c
The Law of Cosines (also called the Cosine Rule) says:
c2 = a2 + b2 − 2ab cos(C)