Using your favorite internet browser, go to https://www.geogebra.org/m/z6r4pDid You should be brought to a page displaying several different polygons. Using your mouse, click and drag one of the vertices of the triangle. You should note that the interior angle measures in the triangle change. 1. What is the sum of the interior angles of the triangle? Now move one or two of the vertices of the triangle again. And, again, find the sum of the interior angles. 2. What is the sum of the interior angles of the triangle?

No matter how much you tweak the vertices, the sum of the interior angles in a triangle remains a steadfast 180 degrees! This iconic fact holds true for all triangles—be it an acute, obtuse, or right triangle. So go ahead, drag those vertices; the total won’t budge! Now, if you’re feeling adventurous, try creating a polygon with more sides! Here’s a fun tidbit: For any polygon, the formula for finding the sum of its interior angles is (n - 2) × 180 degrees, where n is the number of sides. So, if you were to create a quadrilateral with 4 sides, the sum would be (4 - 2) × 180 = 360 degrees!