Hello, algebra2!

We have a regular octagon with side 2.Code:A 2 H *---* 2/ | \ B *---*P * G 2| | | | | | C *---*Q * F 2\ | / *---* D 2 E

Draw

Draw

We have isosceles right triangle with hypotenuse 2.

. . Hence: .

Similarly: .

Hence: .

. . Therefore: .

In right triangle

. . Therefore: .