A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).

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.

-4a - x = a - 7x - 4
-4a = a - 7x - 4 + x
-4a - a = -7x - 4 + x
-5a = -6x - 4
a = \( \frac{-6x - 4}{-5} \)
a = \( \frac{-6x}{-5} \) + \( \frac{-4}{-5} \)
a = 1\(\frac{1}{5}\)x + \(\frac{4}{5}\)

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(8²) + 2π(8 x 5)
sa = 2π(64) + 2π(40)
sa = (2 x 64)π + (2 x 40)π
sa = 128π + 80π
sa = 208π