Side length z =

angle d =

Side length z=20
angle d=53

since they are similar triangles, angles should be the same, therefore,
d=53

if we consider the ration between the sides of the first triangle, its,
6:8:10 = 3:4:5 (when divided by the least common factor; 2)

by applying the same ratio for the second triangle, we can get,
15:20:25 (u can first divide both 15 and 25 by 5 and then multiply each term in 3:4:5 by 5)

therefore, z=20

1. 8 or -82. 14 or -143. -11, -3, 0, 7, 10