Question

in triunghiul ABC , m (<C)=90°, AB=15 cm, AC= 9 cm. calculati a) sin B b) cos B c) tg A d) ctg A

Answer 1

▲ABC, m(C)=90° → AB^2 = AC^2 + BC ^2 → BC^2 = AB^2 - AC^2 → BC^2 = 15^2 - 9^2 → BC^2 = (15 - 9) ( 15 + 9) → BC^2 = 6* 24 → BC^2 = 6*6*4→ BC = 6*2 = 12 (cm)

a)
sin B = AC/AB = 9/15 =3/5
b)
cos B = BC/AB = 12/15 = 4/5
c)
tg A=BC/AC = 12/9 = 4/3
d)
ctg A =AC/BC = 9/12 = 3/4