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 w° = 27, the value of a° is 27.

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.

The formula for circumference is circle diameter x π:

c = πd
c = 19π

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 9 x 3 = \( \frac{27}{2} \) = 13\(\frac{1}{2}\)

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

a = l x w
a = a x b
a = 6 x 8
a = 48