As shown in the diagram of the right triangles below, Triangle: ABC ~ Triangle: DEF, AB = 7x, BC = 4, DE = 7, EF = x. What is thr perimeter of Triangle: DEF to the nearest hundredth?

since triangles are similar
4/x = 7x/7
=》 4/x = x
=》x^2 = 4
=》 x = 2
for right triangles a^2 = b^2+c^2
DF^2 = 7^2+2^2 = 53
=》 DF = 7.28
perimeter of DEF = 7 +2+7.28 = 16.28