Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
Quadrilateral ABCD is cyclic and satisfies
∠
A
+
∠
C
=
180
∘
\angle A+\angle C=180^{\circ}
∠
A
+
∠
C
=
18
0
∘
. Explain briefly why
∠
B
+
∠
D
\angle B+\angle D
∠
B
+
∠
D
is also
180
∘
180^{\circ}
18
0
∘
.
Browse the problem library