A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

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.

(6a)(2ab) + (5a²)(2b)
(6 x 2)(a x a x b) + (5 x 2)(a² x b)
(12)(a¹⁺¹ x b) + (10)(a²b)
12a²b + 10a²b
22a²b

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 1 x 8
a = 8

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.

y + 8 < \( \frac{y}{4} \)
4 x (y + 8) < y
(4 x y) + (4 x 8) < y
4y + 32 < y
4y + 32 - y < 0
4y - y < -32
3y < -32
y < \( \frac{-32}{3} \)
y < -10\(\frac{2}{3}\)