ABC and ADEF are similar. Find the missing side length. E
B
36
72
4
8
А
7
C D
?
F
(The triangles are not drawn to scale.)

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236