Two big ideas of this unit are finding the volume of curved objects and using them to model problems and design solutions.  Both standards, G-GMD.3 & G-MG.3, “live” in Claim 4; therefore, context, using mathematics to model the real-world, and solving problems should be the continual focus.  Depth for finding the volume of curved objects includes examining informal arguments for formulas used, scale factors, cross-sections of 3D objects, and rotations of 2D objects.  The final big idea of this unit is deriving the equation of conic sections.  The design team chose deriving the equation of a circle as an essential standard; however, depth can be explored through the supporting standard of deriving the equation of a parabola.  Deriving equations of conic sections can be an interleaving or reengagement of work done in Unit 5, done here if skipped in Unit 5 or if only deriving the equation of a circle was done in Unit 5 it can be extended here to deriving the equation of a parabola.  Time permitting, work with parabolas could be an excuse to reengage with quadratics from Algebra 1 before students move to Algebra 2 after a “year away from Algebra 1,” especially considering potential gaps in learning due to COVID.