Question

in triangle ABC, AB=AC=15cm and BC=18cm find cos B and cos C.
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Answer 1

Answer:

In triangle ABC, AB = AC = 15 cm and BC = 18 cm then Cos∠ABC = 0.6

Step-by-step explanation:

In triangle ABC, AB = AC = 15 cm and BC = 18 cm then Cos∠ABC = 0.6

Step-by-step explanation:

AB = AC = 15 cm

BC = 18 cm

it is an isosceles triangle

if we draw AD ⊥ from A to line BC

it will bisect BC so BD = 18/2 = 9 cm

Δ ABD will be right angle triangle

with Base BD - 9 cm  & Hypotenuse = AB = 15 cm

∠ABD = ∠ABC  ( as D is a point on line BC)

Cos∠ABC = 9/15

=> Cos∠ABC = 3/5

=> Cos∠ABC = 0.6

hope you understand my question Thankyou!

Answer 2

Answer:

cosb=5/6 and so is cosc=5/6