Ke Shawn is placing a right triangle in the coordinate plane. He knows that the longer leg is twice the length of the shorter leg. He places the longer leg on the x-axis.What coordinates should he assign to the third vertex of the triangle?

the 3rd vertex is on the x axis line which means Y =0 since the longer leg is twice as long as the shorter leg and the length of the shorter leg is a, then twice the length would be 2a ( 2 times a)
 so the 3rd vertex is (2a,0)