The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

A triangle is a three-sided polygon. It has three interior angles that add up to 180° (a + b + c = 180°). An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite (d = b + c). The perimeter of a triangle is equal to the sum of the lengths of its three sides, the height of a triangle is equal to the length from the base to the opposite vertex (angle) and the area equals one-half triangle base x height: a = ½ base x height.

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.

-2z + 7 < 2 + 4z
-2z < 2 + 4z - 7
-2z - 4z < 2 - 7
-6z < -5
z < \( \frac{-5}{-6} \)
z < \(\frac{5}{6}\)

To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.

-2a - 6y = -6a + 5y + 8
-2a = -6a + 5y + 8 + 6y
-2a + 6a = 5y + 8 + 6y
4a = 11y + 8
a = \( \frac{11y + 8}{4} \)
a = \( \frac{11y}{4} \) + \( \frac{8}{4} \)
a = 2\(\frac{3}{4}\)y + 2