Respuesta :

Answer:

BC = 1.71

Step-by-step explanation:

well to start we have to know the relationship between angles, legs and the hypotenuse  in a right triangle

α = 70°

a: adjacent  = BC

h: hypotenuse = 5

sin α = o/h

cos α= a/h

tan α = o/a

we see that it has (angle, adjacent, hypotenuse)

we look at which meets those data between the sine, cosine and tangent

is the cosine

cos α = a/h

Now we replace the values ​​and solve

cos 70 = a/5

0.34202 = a/5

0.34202 * 5 = a

1.7101 = a

round to the neares hundredth

a = 1.7101 = 1.71

BC = 1.71