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 sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 25° - 58° = 97°

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

4a x 3b = (4 x 3) (a x b) = 12ab

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

p = x + y + z
p = 14cm + 10cm + 11cm = 35cm

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce 63 as well and sum (Inside, Outside) to equal -16. For this problem, those two numbers are -9 and -7. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 16y + 63
y² + (-9 - 7)y + (-9 x -7)
(y - 9)(y - 7)