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° = 11, the value of c° is 11.

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

You need to find the value of c so solve the first equation in terms of z:

5c + z = 3
z = 3 - 5c

then substitute the result (3 - 5c) into the second equation:

-3c - 5(3 - 5c) = 3
-3c + (-5 x 3) + (-5 x -5c) = 3
-3c - 15 + 25c = 3
-3c + 25c = 3 + 15
22c = 18
c = \( \frac{18}{22} \)
c = \(\frac{9}{11}\)

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 - 2 = \( \frac{b}{2} \)
2 x (-3b - 2) = b
(2 x -3b) + (2 x -2) = b
-6b - 4 = b
-6b - 4 - b = 0
-6b - b = 4
-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°.