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.

A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).

The volume of a cylinder is πr²h:

v = πr²h
v = π(5² x 7)
v = 175π

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.

-4x - 3 < \( \frac{x}{6} \)
6 x (-4x - 3) < x
(6 x -4x) + (6 x -3) < x
-24x - 18 < x
-24x - 18 - x < 0
-24x - x < 18
-25x < 18
x < \( \frac{18}{-25} \)
x < -\(\frac{18}{25}\)

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

8a x 7b = (8 x 7) (a x b) = 56ab