Chapter 10.1, Problem 8P

Figure 10.33 shows a rectangle subdivided into four triangles. Jonathan says that because the angles in each of the four triangles add to 180°, the angles in the rectangle add to

180°+180°+180°+180°=720°

but Ben says that the angles in a rectangle add to

90°+90°+90°+90°=360°

 

Figure 10.33 A rectangle subdivided into four triangles