If sin A=a/c, how could you use a and c to find cos A

Answer this question! 30 points and brainliest! only if you know the answer.

Hi my sisters and brothers can tell me the answer because i don’t understand the question

Zoey made 5 1/2 cups of trail mix for a camping trip. she wants to divide the trail mix into 3/4 cup servings. a. ten people are going on the trip. can zoey make enough 3/4 cup servings so that each person gets one serving? b. what size would the servings need to be for everyone to have a serving?