Mathematics
In triangle ABC, AB = AC = 15 cm and BC = 18 cm, find cos ∠ABC.
Trigonometric Identities
22 Likes
Answer
In isosceles triangle ABC, the perpendicular drawn from angle A to the side BC divides BC into 2 equal parts.
BD = DC = = 9
cos ∠ABC =
Hence, cos ∠ABC = .
Answered By
18 Likes
Related Questions
In the diagram, given below, triangle ABC is right-angled at B and BD is perpendicular to AC. Find :
(i) cos ∠DBC
(ii) cot ∠DBA
In the given figure, triangle ABC is right-angled at B. D is the foot of the perpendicular from B to AC. Given that BC = 3 cm and AB = 4 cm. Find :
(i) tan ∠DBC
(ii) sin ∠DBA
In the figure, given below, ABC is an isosceles triangle with BC = 8 cm and AB = AC = 5 cm. Find :
(i) sin B
(ii) tan C.
(iii) sin2 B + cos2 B
(iv) tan C - cot B
In triangle ABC; ∠ABC = 90°, ∠CAB = x°, and BC = 15 cm. Find the measures of AB and AC.