Find the possible values of the constant k if the roots of the quadratic equation x^2 - (k+2)x + 4 =0 are equal ​

Acentral angle measuring 160 degrees intercepts an arc in a circle whose radius is 4. what is the length of the arc the circle formed by this central angle? round the length of the arc to the nearest hundredth of a unit. a) 4.19 units b) 6.28 units c) 12.57 units d) 12.57 square units