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.

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

a = l x w
a = a x b
a = 9 x 5
a = 45

The volume of a cylinder is πr²h:

v = πr²h
v = π(6² x 4)
v = 144π

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce -54 as well and sum (Inside, Outside) to equal 3. For this problem, those two numbers are -6 and 9. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 3y - 54
y² + (-6 + 9)y + (-6 x 9)
(y - 6)(y + 9)

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.