Consider a triangle ABC like the one below. Suppose that C=31°, c= 27, and b = 38. Solve the triangle. Carry your intermediate computations to at least four decimal places, and round your answers to the nearest tenth. If there is more than one solution, use the button labeled "or".

Respuesta :

Step-by-step explanation:

I don't see a triangle here.

but based on the given information we can rely on the law of cosine (which I call the general Pythagoras) :

c² = a² + b² - 2ab×cos(C)

where C is the angle opposite to the side c, a and b are the other 2 sides.

and we can rely on the law of sine :

a/sinA = b/sinB = c/sinC

where A, B, C are the angles opposite of the corresponding sides a, b, c.

also remember, the sum of all angles in a triangle is always 180°.

so, we can start with

c/sinC = b/sinB

27/sin(31) = 38/sin(B)

sin(B) = 38×sin(31)/27 = 0.724868402...

B = 46.45790151...° ≈ 46.5°

or (as I cannot see the model triangle) it can be an obese angle 180 - 46.45790151... = 133.5420985... ≈ 133.5°

this is because sine is positive in the first and second quadrant, and the sine of the angles x and 180-x have the same value.

that gives us for the angle A :

180 = 31 + 46.5 + A

A = 102.5°

or

180 = 31 + 133.5 + A

A = 15.5°

and for side a

a² = b² + c² - 2bc×cos(A) =

= 38² + 27² - 2×38×27×cos(102.5) =

= 1444 + 729 - 2052×-0.216439614... =

= 2,617.134088...

a = 51.15793279... ≈ 51.2

or

a² = b² + c² - 2bc×cos(A) =

= 38² + 27² - 2×38×27×cos(15.5) =

= 1444 + 729 - 2052×0.963630453... =

= 195.63031...

a = 13.98679055... ≈ 14.0

so, the complete triangle is

A = 102.5°

or

A = 15.5°

B = 46.5°

or

B = 133.5°

C = 31°

a = 51.2

or

a = 14.0

b = 38

c = 27