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 area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(6 + 8)(4)
a = ½(14)(4)
a = ½(56) = \( \frac{56}{2} \)
a = 28

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.

(9a)(5ab) - (5a²)(5b)
(9 x 5)(a x a x b) - (5 x 5)(a² x b)
(45)(a¹⁺¹ x b) - (25)(a²b)
45a²b - 25a²b
20a²b

According to the Pythagorean theorem, the hypotenuse squared is equal to the sum of the two perpendicular sides squared:

c² = a² + b²
c² = 9² + 6²
c² = 81 + 36
c² = 117
c = \( \sqrt{117} \)

The area of a parallelogram is equal to its length x width:

a = l x w
a = a x b
a = 1 x 2
a = 2