Why Should that Convince Me?: Teaching Toulmin Analysis Across the Curriculum

Abstract

This shape appears to be a square, but we have to make sure. 7) Recall that our triangle is isosceles with a right angle, so the two remaining angles have the same angle measure. 8) Moreover, in any triangle the angles add up to 180 degrees, so the two smaller angles (which have the same angle measure) add up to 90 degrees --so each of the 4 corners is 90 degrees. 9) We can also see that each side of our shape is length ", so the 4 triangles form a square. Then the area of the 4 triangles is also equal to the area of the square: " ! . 10) Now rearranging the triangles won't change their area, so the two area formulas must be equal, therefore:11) The same reasoning holds for any isosceles right triangle, so the relationship between the side lengths holds for any isosceles right triangle.