This is a right triangle. which expression is equivalent to sin a? a: sin theta b: cos a c: cos theta d: tan a

its either a or d. do u have any other information? ?

b. astronomers

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: