The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 8cm + 8cm + 6cm = 22cm

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).

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 < sign and the answer on the other.

-3x + 9 < \( \frac{x}{-8} \)
-8 x (-3x + 9) < x
(-8 x -3x) + (-8 x 9) < x
24x - 72 < x
24x - 72 - x < 0
24x - x < 72
23x < 72
x < \( \frac{72}{23} \)
x < 3\(\frac{3}{23}\)

The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{6}{2} \)
r = 3
a = πr²
a = π(3²)
a = 9π

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).