Someone math

the circumference of a circle is 3π in.

what is the area of the circle?

1.5π in²
2.25π in²
6πin²
9π in²

We just started the introduction into circles and i have no idea how to do this.

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50.

Let u = {q, r, s, t, u, v, w, x, y, z} a = {q, s, u, w, y} b = {q, s, y, z} c = {v, w, x, y, z}. list the elements in the set. a ∩ (b ∪ c)a) {q, s, w, y}b) {q, y, z}c) {q, s, u, w, y, z}d) {q, r, w, y, z}