An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

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

sa = 2πr² + 2πrh
sa = 2π(2²) + 2π(2 x 2)
sa = 2π(4) + 2π(4)
sa = (2 x 4)π + (2 x 4)π
sa = 8π + 8π
sa = 16π

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

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.

a - 5 = \( \frac{a}{-1} \)
-1 x (a - 5) = a
(-1 x a) + (-1 x -5) = a
-a + 5 = a
-a + 5 - a = 0
-a - a = -5
-2a = -5
a = \( \frac{-5}{-2} \)
a = 2\(\frac{1}{2}\)

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

z² + 8z + 12 = 0
(z + 2)(z + 6) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 2) or (z + 6) must equal zero:

If (z + 2) = 0, z must equal -2
If (z + 6) = 0, z must equal -6

So the solution is that z = -2 or -6