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° = 145, the value of w° is 35.

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 2 + 2 + 9 + 6
p = 19

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 equal sign and the answer on the other.

3b - 5 = -9 - 4b
3b = -9 - 4b + 5
3b + 4b = -9 + 5
7b = -4
b = \( \frac{-4}{7} \)
b = -\(\frac{4}{7}\)

An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.

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 equal sign and the answer on the other.

7x - 1 = \( \frac{x}{-2} \)
-2 x (7x - 1) = x
(-2 x 7x) + (-2 x -1) = x
-14x + 2 = x
-14x + 2 - x = 0
-14x - x = -2
-15x = -2
x = \( \frac{-2}{-15} \)
x = \(\frac{2}{15}\)