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 formula for circumference is circle diameter x π. Circle diameter is 2 x radius:

c = πd
c = π(2 * r)
c = π(2 * 14)
c = 28π

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

a = l x w
a = a x b
a = 3 x 6
a = 18

You need to find the value of a so solve the first equation in terms of y:

-5a + y = -7
y = -7 + 5a

then substitute the result (-7 - -5a) into the second equation:

3a - 2(-7 + 5a) = 8
3a + (-2 x -7) + (-2 x 5a) = 8
3a + 14 - 10a = 8
3a - 10a = 8 - 14
-7a = -6
a = \( \frac{-6}{-7} \)
a = \(\frac{6}{7}\)

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°).