Question

To do with COS, TAN and SIN

Answer 1

Answer:

Step-by-step explanation:

$\frac{AB}{BC} =cos 71\\BC=\frac{AB}{cos 71} =\frac{6.3}{cos71} \approx 19.351$

Answer 2

The answers are BC = 6.3/ cos71 = 19.351 and BC = 6.3 / sin 19 = 19.351

Step-by-step explanation:

cosB = $\frac{base}{hypoteneus}$

or, cos 71 = $\frac{AB}{BC}$

or,BC = $\frac{AB}{cos71}$

= 6.3/ cos71 = 19.351

Here, ∠C = 180 - (90 + 71 ) = 19

sin19 =$\frac{perpendicular}{hypoteneus}$

or, sin 19 = AB/ BC

or, BC = AB /sin 19

= 6.3 / sin 19 = 19.351

We cannot find BC in terms of tan as tan means perpendicular/ hypotenuse. BC is the hypotenuse and that is got eliminated.

Here is the explanation.