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).

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(6 + 8)(3)
a = ½(14)(3)
a = ½(42) = \( \frac{42}{2} \)
a = 21

To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.

2a + 5y = 8a + 8y - 6
2a = 8a + 8y - 6 - 5y
2a - 8a = 8y - 6 - 5y
-6a = 3y - 6
a = \( \frac{3y - 6}{-6} \)
a = \( \frac{3y}{-6} \) + \( \frac{-6}{-6} \)
a = -\(\frac{1}{2}\)y + 1

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.

2z - 9 = \( \frac{z}{-2} \)
-2 x (2z - 9) = z
(-2 x 2z) + (-2 x -9) = z
-4z + 18 = z
-4z + 18 - z = 0
-4z - z = -18
-5z = -18
z = \( \frac{-18}{-5} \)
z = 3\(\frac{3}{5}\)

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, 4) and (2, -6) so the slope becomes: