Really, really need help ASAP. Prove that the sum of the measures of the interior angles of a triangle is 180°. Be sure to create and name the appropriate geometric figures.
I've seen examples but I don't understand it or the answer.

Alarge rectangle is divided into four smaller rectangles.

Arestaurant offers a $12 dinner special that has 5 choices for an appetizer, 12 choices for an entrée, and 4 choices for a dessert. how many different meals are available when you select an appetizer, an entrée, and a dessert? a meal can be chosen in nothing ways. (type a whole number.)

Solve 2x2 + 8 = 0 by graphing the related function. there are two solutions: . there are no real number solutions. there are two solutions: 2 and -2