Help please, i dont know this :)

What can be said about the relationship between triangles and circles? check all that apply. a) many circles can be inscribed in a given triangle b) exactly one triangle can be inscribed in a given circle c) exactly one circle can be inscribed in a given triangle d) many triangular shapes can be circumscribed about a given circle

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

6cm10 cma conical paper cup has dimensions as shown in the diagram. how much water can the cup hold when full?