[기하벡터 #27(2)] 공간도형/레벨-2

[기하벡터 #27(2)] 공간도형/레벨-2

[공간도형 단면화]--------------------------------------------------

[레벨2-1]--------------------------------------------------------------------

[레벨2-2]--------------------------------------------------------------------

[풀이]-------------------------

[공간도형]--->[단면화]--->{3수선정리,이면각]--->[직각 삼각형]