standard_description: Solve real-world and mathematical problems involving area, volume and surface area of two- and three-dimensional objects composed of triangles, quadrilaterals, polygons, cubes, and right prisms.
problem_activity: Task
About how many cells are in the human body?
You can assume that a cell is a sphere with radius 10$^{-3}$cm and that the density of a cell is approximately the density of water which is 1g/cm$^3$.


aligns: no