The formula for area is πr²:

a = πr²
a = π(5²)
a = 25π

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

c² + c - 56 = 0
(c - 7)(c + 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 7) or (c + 8) must equal zero:

If (c - 7) = 0, c must equal 7
If (c + 8) = 0, c must equal -8

So the solution is that c = 7 or -8

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 Pythagorean theorem defines the relationship between the side lengths of a right triangle. The length of the hypotenuse squared (c²) is equal to the sum of the two perpendicular sides squared (a² + b²): c² = a² + b² or, solved for c, \(c = \sqrt{a + b}\)

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.