The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

y² - 12y + 27 = 0
(y - 3)(y - 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 3) or (y - 9) must equal zero:

If (y - 3) = 0, y must equal 3
If (y - 9) = 0, y must equal 9

So the solution is that y = 3 or 9

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

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 2 x 1) + (2 x 1 x 2) + (2 x 2 x 2)
sa = (4) + (4) + (8)
sa = 16

For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• 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°)

Applying these relationships starting with y° = 154, the value of c° is 26.

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.