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.

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.

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).

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

sa = 2πr² + 2πrh
sa = 2π(1²) + 2π(1 x 7)
sa = 2π(1) + 2π(7)
sa = (2 x 1)π + (2 x 7)π
sa = 2π + 14π
sa = 16π