110,163 views
40 votes
40 votes
Need help solving thisIt’s a practice from my ACT prep guide online

Need help solving thisIt’s a practice from my ACT prep guide online-example-1
User CreatoR
by
3.0k points

1 Answer

17 votes
17 votes

If angles C and D are the acute angles of a right triangle, we have the image as shown below:

The question gives that:


\sin D=(2)/(7)

Comparing with the Sine Trigonometric Ratio given to be:


\sin \theta=(opp)/(hyp)

we thus have that the Sine ratio of angle D in the triangle drawn above will be:


\sin D=(d)/(b)

Hence, we can have the triangle look as shown below:

Therefore, the cosine of angle C, with the ratio:


\cos C=(adj)/(hyp)

will be given to be:


\cos C=(2)/(7)

Therefore, the correct option is the FIRST OPTION.

Need help solving thisIt’s a practice from my ACT prep guide online-example-1
Need help solving thisIt’s a practice from my ACT prep guide online-example-2
User Cleroo
by
3.1k points