Step-by-step explanation:
because VW || YZ, the 2 triangles are similar.
this is given by the rules of equal angles of intersecting lines with parallel lines. Z to V and Y to W would be such intersecting lines.
and therefore, the angle at W is the angle at Y, the angle at V is the angle at Z. and therefore both angles at A are equal.
so, for similar triangles the scaling factor between corresponding pairs of sides is the same for all sides.
e.g. the same scaling factor that converts 7.2 to 12, converts then also x to x+4.
7.2 × f = 12
f = 12/7.2 = 12/ 72/10 = 120/72 = 10/6 = 5/3
x × 5/3 = x + 4
5x = 3x + 12
2x = 12
x = 6
A to Y = x = 6
W to A = x + 4 = 6 + 4 = 10
