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

a = l x w
a = a x b
a = 8 x 9
a = 72

Parallel lines are lines that share the same slope (steepness) and therefore never intersect. A transversal occurs when a set of parallel lines are crossed by another line. All of the angles formed by a transversal are called interior angles and angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°) and are called corresponding angles. Alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°) and 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°).

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(7 + 3)(4)
a = ½(10)(4)
a = ½(40) = \( \frac{40}{2} \)
a = 20

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.

(2a)(9ab) + (3a²)(8b)
(2 x 9)(a x a x b) + (3 x 8)(a² x b)
(18)(a¹⁺¹ x b) + (24)(a²b)
18a²b + 24a²b
42a²b

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.

5a - 9 > \( \frac{a}{1} \)
1 x (5a - 9) > a
(1 x 5a) + (1 x -9) > a
5a - 9 > a
5a - 9 - a > 0
5a - a > 9
4a > 9
a > \( \frac{9}{4} \)
a > 2\(\frac{1}{4}\)