total internal reflection全内反射 prisms棱镜 right isosceles
of triangles scalene triangle ╟ no sides congruent isosceles
要点全析等腰三角形 1等腰三角形(isosceles triangle) 有两条边相等
figure 3b-16) shall consist of a row of solid white isosceles
10 vertices decagons regular polygon irregular polygon isosceles