A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

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.

-7y - 8 < \( \frac{y}{-8} \)
-8 x (-7y - 8) < y
(-8 x -7y) + (-8 x -8) < y
56y + 64 < y
56y + 64 - y < 0
56y - y < -64
55y < -64
y < \( \frac{-64}{55} \)
y < -1\(\frac{9}{55}\)

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

A trapezoid is a quadrilateral with one set of parallel sides.

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.

(5a)(4ab) + (7a²)(4b)
(5 x 4)(a x a x b) + (7 x 4)(a² x b)
(20)(a¹⁺¹ x b) + (28)(a²b)
20a²b + 28a²b
48a²b