Jawab:

cos p = 2/3 (p sudut lancip)

cos p = samping/miring

tan p = depan/samping

Rumus phytagoras (pada segitiga siku-siku):

a² + b² = c²

a = tinggi

b = alas

c = sisi miring

cos p = 2/3

sisi samping = 2 = b

sisi miring = 3 = c

sisi depan (depan sudut p) = a

a² + b² = c²

a² = c² - b²

a² = 3² - 2²

a² = 9 - 4

a² = 5

a = √5

sisi depan = √5

tan p = depan/samping

tan p = √5/2

tan p = 1/2 √5

atau:

sec p = 1/(cos p)

sec p = 1/ (2/3)

sec p = 1 x 3/2 = 3/2

tan²p = sec²p - 1

tan²p = (3/2)² - 1

tan²p = 9/4 - 1

tan²p = 9/4 - 4/4 = 5/4

tan p = √(5/4)

tan p = √5 / √4

tan p = √5/2

tan p = 1/2 √5