The angles and lengths of each of the given triangles are;
5) m∠B = 57.52°
6) B = 70.81°
7) AB = 55.43 Km
8) AC = 39.06 ft
How to use cosine rule?
The cosine rule is expressed as;
c = √[a² + b² - 2ab(cos C)]
5) Using cosine rule;
BC = √[21² + 13² - 2(21*13)(cos 91)]
BC = 24.89
Using sine rule, we can find angle B as;
21/sin m∠B = 24.89/sin 91
sin m∠B = (21 * sin 91)/24.89
sin m∠B = 0.8436
m∠B = sin⁻¹0.8436
m∠B = 57.52°
6) Using cosine rule;
14² = 11² + 13² - 2(11*13)(cos B)]
196 = 121 + 169 - 286(cos B)
cos B = (121 + 169 - 196)/286
cos B = 0.3287
B = cos⁻¹0.3287
B = 70.81°
7) Using cosine rule;
AB = √[24² + 36² - 2(24*36)(cos 134)]
AB = 55.43 Km
8) Using cosine rule;
AC = √[21² + 26² - 2(21*26)(cos 112)]
AC = 39.06 ft
Read more about cosine rule at; https://brainly.com/question/4372174
#SPJ1
