In a regular hexagonal pyramid SABCDEF, the base side AB=4, and the side edge SA=7. Point M lies on edge BC, with BM=1, point K lies on edge SC, with SK=4. a) Prove that the MKD plane is perpendicular to the plane of the base of the pyramid. b) Find the volume of the pyramid AB=40.
Q. In a regular hexagonal pyramid SABCDEF, the base side AB=4, and the side edge SA=7. Point M lies on edge BC, with BM=1, point K lies on edge SC, with SK=4. a) Prove that the MKD plane is perpendicular to the plane of the base of the pyramid. b) Find the volume of the pyramid AB=40.
Identify Properties: Identify the properties of a regular hexagonal pyramid. In this pyramid, all base sides are equal, and all side edges are equal. The base is a regular hexagon, and the apex is directly above the center of the base.
Calculate Height: Calculate the height of the pyramid using the Pythagorean theorem in triangle SAB, where SA is the slant height, AB/2 is half the base of the hexagon, and SO is the height of the pyramid. Using SA = 7 and AB = 4, we find SO:SO=SA2−(AB/2)2=72−(4/2)2=49−4=45≈6.71.
Determine Coordinates: Determine the coordinates for points M and K. Since M is on BC and BM=1 (with BC=4), M divides BC in the ratio 1:3. Point K is on K0 with K1, and K2, so K divides K0 in the ratio K5.
Establish Vectors: Establish the vectors for MK and a base edge (like AB). Calculate the dot product to check if MK is perpendicular to the base. If the dot product is 0, MK is perpendicular to the base.