Answer:
The value of c is 10.9 ⇒ 3rd answer
Step-by-step explanation:
* Lets study the problem
* In ΔABC
- a, b, c are the lengths of its 3 sides, where
# a is opposite to angle A ⇒ BC
# b is opposite to angle B ⇒ AC
# c is opposite to angle C ⇒ AB
- m∠C = 68°
- a = 8 ⇒ side BC
- b = 11 ⇒ side AC
- Find the value of c ⇒ side AB
* We have the length of two sides and the measure of the
including angle between them and we want to find the
length of the side opposite to this angle then the cosine
rule is the perfect way
∵ c² = a² + b² - 2ab cos(C)
∵ a = 8 , b = 11 and m∠C = 68°
∴ c² = (8)² + (11)² -2(8)(11) cos(68°)
∴ c² = 119.069 ⇒ take √ for both sides
∴ c = 10.9 units
* The value of c is 10.9
