(edit: I sill need help, despite length of post)Can anybody check my answers? (geometry/trig)

Question

anonymous · Answer

Which pair of angles has congruent values for the sin x° and the cos y°?

 70°; 160°

 70°; 70

 70°; 120°

 70°; 20°

anonymous · Answer

I said D.

anonymous · Answer

Calculate the area of triangle ABC with altitude CD, given A (−3, −4), B (−6, 2), C (0, 0), and D (−4, −2).

 14 square units

 15 square units

 18 square units

 20 square units

anonymous · Answer

I said A.

campbell_st · Answer

well there is a property is triangles 

perhaps this diagram may help

|dw:1400617760825:dw|

anonymous · Answer

sin(x)= o/h ; cos(90-x)=a/h is that what you mean??

campbell_st · Answer

thats it... cos(x) = sin(90 - x)

anonymous · Answer

so D would be right?

anonymous · Answer

@amistre64 @e.mccormick @wolfe8 ?

parthkohli · Answer

Apparently not.  Do you see two angles that have a difference of 90 degrees?

anonymous · Answer

oh. for some reason I was thinking it should = 90 degrees

anonymous · Answer

so it'd be A, but was the image they added relevant?

parthkohli · Answer

Yes.

parthkohli · Answer

It showed you how cos(90 - x) = sin(x).

anonymous · Answer

oh ok

anonymous · Answer

thanks. what about my second question?