Answer:
The side opposite angle C
Step-by-step explanation:
The angles of a triangle must add up to equal 180°. So 180=59+57+x
180=116+x
x=64°
In a triangle the smallest side is always opposite the smallest angle
Sometimes it will, and sometimes it won't.
I reason as follows:
(21 + x) + (30 + 2x) = 51 + 3x has an 'x' term
(42 + x) + (30 - x) = 72 has no 'x' term.