Question:
The distance between places $B$ and $C$ on opposite sides of a river is $20$ meters. The measure of the angle $\alpha=\angle ACB$ is $64^{\circ}$. From the given expressions, select all that represent the width of the river:
Project ID:
7400120113
Answer 1:
$20\cdot \sin 64 ^{\circ}$
Answer 1 Correct:
1
Answer 2:
$20 \cdot \cos 64 ^{\circ}$
Answer 2 Correct:
0
Answer 3:
$20\cdot \mathrm{tg}\, 64 ^{\circ}$
Answer 3 Correct:
0
Answer 4:
$20 \cdot \mathrm{cotg} \, 64 ^{\circ}$
Answer 4 Correct:
0
Answer 5:
$20\cdot \cos 26 ^{\circ}$
Answer 5 Correct:
1
Answer 6:
$\frac{20}{\sin 64 ^{\circ}}$
Answer 6 Correct:
0
Answer 7:
$\sqrt{20^2-(20\cdot \cos 64 ^{\circ} )^2}$
Answer 7 Correct:
1
Answer 8 Correct:
0