1. Yes, △LMN is similar to △WXY because 21/30 = 7/10 = 28/40 and the included angles are equal because they are both 90°, so by the SAS similarity theorem, the two triangles are similar.
2. The one with the larger base, which is the one with △WXY as the base, will have the greater volume.
volume of smaller prism = (area of base) * (height)
volume of smaller prism = (1/2 * 30 * 21) * (height)
volume of smaller prism = (315) * (height)
volume of smaller prism = 315h , where h is the height of the prism
volume of larger prism = (area of base) * (height)
volume of larger prism = (1/2 * 40 * 28) * (height)
volume of larger prism = (560) * (height)
volume of larger prism = 560h
The larger prism is how many times greater than the smaller prism? That is, 560h is how many times greater than 315h ?
560h/315h = 16/9 so... 560h = (16/9) * 315h
In other words, 560h is 16/9 times 315h , which means the volume of the larger larger prism is 16/9 times the volume of the smaller prism.