How to solve basic trigonometry?

Assuming angle N = 90°

a) ∠m = 48°

b) n = 20.18

c) k = 13.5

Step-by-step explanation:

a) ∠m = 180° - 90° - 42° = 48°  because the sum of all three interior angles of a triangle equals 180°

b) cos 42 = 15/n

0.7431 = 15/n

n = 20.18

c) tan 42 = k/15

0.9004 = k/15

k = 13.5

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: