A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

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(3²) + 2π(3 x 1)
sa = 2π(9) + 2π(3)
sa = (2 x 9)π + (2 x 3)π
sa = 18π + 6π
sa = 24π

A trapezoid is a quadrilateral with one set of parallel sides.

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

y² - 4y - 76 = -5y - 4
y² - 4y - 76 + 4 = -5y
y² - 4y + 5y - 72 = 0
y² + y - 72 = 0

Next, factor the quadratic equation:

y² + y - 72 = 0
(y - 8)(y + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 8) or (y + 9) must equal zero:

If (y - 8) = 0, y must equal 8
If (y + 9) = 0, y must equal -9

So the solution is that y = 8 or -9