Answer:
β = arccos((a^2 + c^2 - b^2)/(2·a·c))
β = arccos((3^2 + 7^2 - 5^2)/(2·3·7)) = 38.21°
Answer:
b = 38.22
Step-by-step explanation:
In the given triangle ABC, a = 3, b = 5 and c = 7 is given.
We have to find the measure of angle b.
To get the measure of any angle we will apply cosine rule in the triangle.
b² = a² + c² - 2ac(cosb)
5² = 3² + 7² - 2×3×7×cosb
25 = 9 + 49 - 42×cosb
25 = 58 - 42cosb
-42cosb = 25 - 58 = -33
cosb = [tex]\frac{33}{42}[/tex]
cosb = 0.7856
[tex]b= cos^{-1}(0.7856)[/tex]
b = 38.22
b = 38.22 is the correct answer.
