Which of the following describes a compound event?

Which addition property is being illustrated below? (type commutative or associative) (6 + 7) + 1 = 6 + (7 + 1)

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

Asquare has a perimeter of sixteen centimeters. what is the length of each of its sides? a. 8 cm c. 9 cm b. 4 cm d. 10 cm select the best answer from the choices