For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other
• same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°)

Applying these relationships starting with x° = 149, the value of a° is 31.

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

c = πd
c = π(2 * r)
c = π(2 * 17)
c = 34π

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

a = ½bh
a = ½ x 8 x 8 = \( \frac{64}{2} \) = 32

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.

z + 1 < \( \frac{z}{6} \)
6 x (z + 1) < z
(6 x z) + (6 x 1) < z
6z + 6 < z
6z + 6 - z < 0
6z - z < -6
5z < -6
z < \( \frac{-6}{5} \)
z < -1\(\frac{1}{5}\)

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.