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MathNet 2016-part-04 — 184 problems (EN–VI) Question 76

Math Olympiad Vault · MathNet 2016-part-04 — 184 problems (EN–VI)

Question 76

The regular triangular pyramid $SABC$ has $AB = a$, $M$ and $N$ are the midpoints of the sides $[AB]$ and $[BC]$ respectively and $SA \perp (SBC)$.

a) Find the measure of the angle of the line $SM$ with the plane $(SAN)$.

b) If $SP$ is the orthogonal projection of the segment $SM$ on the plane $(SAN)$, compute the tangent of the angle of the planes $(SPC)$ and $(ABC)$.