tlong di jawab soal no 8-10 pakai cara

7.
AB = 2 - (-4) = 6
BC = 2 - (-2) = 4

ABC segitiga siku-siku
AC² = 4² + 6² = 52
AC = 2√13

Cos A = AB/AC = 3√13

8.
sin α = -2/3

cari sisi satu lagi

x² = 3² - 2² = 9 - 4 = 5
x = √5

(kuadran III, cos (-))
cos α = -√5/3

9.
π = 180°
3/4 π = sin 135 => kuadran II
sin 135 - cos 135 = 1/2 √2 - (-1/2 √2) = √2

10.
sin 30° = p/8
p = 8 x 1/2 = 4