The ratio is 12:16, which, when simplified, is 3:4.
For every three girls, there are four boys.
The pyhtagorean states that to find c, use the eqaution,

.
Substitute 1 for a and 20 for b;
c^2=1+400
c^2=401
c=
which is about 20.02
Hope this helps.
Answer:
3x+2°=65° (vert opp angles)
3x=65°-2°
=63°
x=63÷3
=21
Does is have a total perimeter of the triangle? If not, the closest you can get is by simplifying.
2x+3x-1+4x+5
9x+4