The formula for circumference is circle diameter x π. Circle diameter is 2 x radius:

c = πd
c = π(2 * r)
c = π(2 * 12)
c = 24π

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 7 x 1 = \( \frac{7}{2} \) = 3\(\frac{1}{2}\)

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the > sign and the answer on the other.

-4a - 4 > 8 - 2a
-4a > 8 - 2a + 4
-4a + 2a > 8 + 4
-2a > 12
a > \( \frac{12}{-2} \)
a > -6

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

-2z - 6 = -1 + 3z
-2z = -1 + 3z + 6
-2z - 3z = -1 + 6
-5z = 5
z = \( \frac{5}{-5} \)
z = -1

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y + 2)(y + 2)
(y x y) + (y x 2) + (2 x y) + (2 x 2)
y² + 2y + 2y + 4
y² + 4y + 4