Parallel lines are lines that share the same slope (steepness) and therefore never intersect. A transversal occurs when a set of parallel lines are crossed by another line. All of the angles formed by a transversal are called interior angles and angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°) and are called corresponding angles. Alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°) and 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°).

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

9c + z = 3
z = 3 - 9c

then substitute the result (3 - 9c) into the second equation:

2c + 3(3 - 9c) = -7
2c + (3 x 3) + (3 x -9c) = -7
2c + 9 - 27c = -7
2c - 27c = -7 - 9
-25c = -16
c = \( \frac{-16}{-25} \)
c = \(\frac{16}{25}\)

The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 1) and (2, -9) so the slope becomes:

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).