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

p = x + y + z
p = 13cm + 11cm + 9cm = 33cm

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).

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 8 + 7 + 8 + 2
p = 25

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

c² + 6c + 8 = 0
(c + 2)(c + 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c + 2) or (c + 4) must equal zero:

If (c + 2) = 0, c must equal -2
If (c + 4) = 0, c must equal -4

So the solution is that c = -2 or -4

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 1 x 2 = \( \frac{2}{2} \) = 1