Idon't understand my math class..and she left me with this problem. so how do i solve this?

An objects motion is described by the equation d= 4sin (pi t) what will the height of the object be at 1.75 seconds?

If sr is 4.5cm and tr is 3cm, what is the measure in degrees of angle s?

Consider a bag that contains 220 coins of which 6 are rare indian pennies. for the given pair of events a and b, complete parts (a) and (b) below. a: when one of the 220 coins is randomly selected, it is one of the 6 indian pennies. b: when another one of the 220 coins is randomly selected (with replacement), it is also one of the 6 indian pennies. a. determine whether events a and b are independent or dependent. b. find p(a and b), the probability that events a and b both occur.