The rule that refers to grouping is blank property

associative property

Step-by-step explanation:

Grouping like this

a + (b + c) = (a + b) + c

or

a(bc) = (ab)c

is the associative property

Answer= Associative Property

Step-by-step explanation:

Affiliate. The word "associative" comes from "associate" or "group"; the Associative Property is the rule that refers to grouping. For addition, the rule is "a + (b + c) = (a + b) + c"; in numbers, this means 2 + (3 + 4) = (2 + 3) + 4.

c

step-by-step explanation:

60°

step-by-step explanation:

the measure angle of c in an isosceles triangle abc is 60° because in isosceles triangle,the measures of all the angles is 60°.