Answer:
161700 ways.
Step-by-step explanation:
The order in which the transistors are chosen is not important. This means that we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

In this question:
3 transistors from a set of 100. So

So 161700 ways.
Angle c (36 degree) is equal to angle a
Angle a=36 degree
a+b=180
b=180-36
b=144 degree
Angle b=144 degree
(3/20)^3
27/8000
..............