1. right triangle?
-> c²= g²+b²
c²= 20²+21²
c²= 841
c=V841
c=29
-> triangle BCG is right
2.
cos B= 20/29
tan B= 21/20
sin B= 21/29
sin G= 20/29
cos G= 21/29
tan G= 20/21
