it is right triangle because x° 2x° and another 2x° would be a (n). the triangle has sides on them, it would measure out to 3,4 and 6. which would be the type of triangle this is a right trinagle. hopefully this helps! ^^
Multiples of 15 are: 15,30,45,60,75,90,105,120,135,150,165,180,195,210,225,240,255,270,285,300,315,330,345,360,375,390,405,420,435,450,465,480,495,510,525,540,555,570,585,600,615,630,645,660,675,690,705,720,735,