Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
Prove that the angle which the external bisector of
∠
A
\angle A
∠
A
of
△
A
B
C
\triangle ABC
△
A
B
C
makes with
B
C
BC
B
C
is half the difference of
∠
B
\angle B
∠
B
and
∠
C
\angle C
∠
C
.
Browse the problem library