Which statement is true?

In any right triangle, the sine of one acute angle is equal to the cosine of the other acute angle.

In any right triangle, the sine of one acute angle is equal to the sine of its complementary angle.

In any right triangle, the cosine of one acute angle is equal to the cosine of its complementary angle.

In any right triangle, the sum of the sine of one acute angle and the cosine of the other acute angle is 1.

Question

Which statement is true?

In any right triangle, the sine of one acute angle is equal to the cosine of the other acute angle.

In any right triangle, the sine of one acute angle is equal to the sine of its complementary angle.

In any right triangle, the cosine of one acute angle is equal to the cosine of its complementary angle.

In any right triangle, the sum of the sine of one acute angle and the cosine of the other acute angle is 1.

anonymous · Answer

D i think

anonymous · Answer

yea thanks man

wolf1728 · Answer

No I don't think D
sine 45 = .707
cosine 45 = .707
Sum does NOT = 1

wolf1728 · Answer

sine 10 = .17365
cosine 80 = .17365
sum NOT = 1

wolf1728 · Answer

Seems like it might be A
Not sure

wolf1728 · Answer

Anyone else care to give an answer?

anonymous · Answer

@wolf1728 is correct, it's A. Those are cofunction identities.
$$\cos(90^o-\theta)=\sin \theta$$
$$\sin(90^o-\theta)=\cos \theta$$