In s-abc, triangle △ ABC is an equilateral triangle with side length 4, plane sac ⊥ plane ABC, SA = SC = 2, M is the midpoint of ab (1) Find the size of dihedral angle s-cm-a; (2) find the distance from point B to surface SCM

If SD ⊥ AC is set to D through s, it is easy to know that SD = 2
Because both sides are vertical, SD is perpendicular to ABC
Then D is used for de vertical MC
MC is vertical to AB, De is vertical to MC, and D is the midpoint
So De is the median of AMC, = 1
tanS-CM-A=2/1=2
(2) If you calculate the BSCM volume and SCM area, you can calculate the distance. I won't go into details

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