Answer:
Third answer choice is correct: 8/17
Step-by-step explanation:
You have to know the "parts" of the triangle: three angles, A B & C + three sides, labelled with measures 8, 15 & 17
Also, this is a right triangle (90 degree angle in the bottom left corner)
Also, since you're asked about angle A in the question (it asks What is the ratio of cosA), you have to know that the "8" side is adjacent to angle A and the "17" side is the hypotenuse (hypotenuse is always opposite the 90 degree angle)
Finally, with the mnemonic SOH-CAH-TOA (to help you remember how to find sin, cos & tan), you know the ratio of the cosine of angle A (cosA) is Adjacent over Hypotenuse or 8 over 17 (the fraction 8/17)
