What is the measurement of BC?

Question

In right triangle ABC, ∠C is a right angle, m∠B=70∘, and AB=13

sin70∘≈0.94

cos70∘≈0.34

tan70∘≈2.75

There is a right triangle, ABC, that has the given hypotenuse length of AB of 13 and the given angle measurement of B that is 70 degrees.

What is the measurement of BC?

if necessary, round your answer to one decimal place, like this: 42.5

Answer 1

c=13

β=70°

γ=90°

α=20°

a/sinα=b/sinβ=c/sinγ

a/.342=13 (sin of a rt >=1)

a=4.446

c^2-a^2=b^2

169-19.769=149.23^.5=12.216=b

Answer 2

BC/13 = cos 70°

BC/13 = 0.34

BC = (13)(0.34)