In the 1880s, Marvin Stone drank his mint julep using what was then the standard tool, a piece of rye grass. However, he did not like the residue caused by the grass disintegrating in the liquid. His solution was to wrap strips of paper around a pencil and glue them together, creating the first drinking straw. Most straws nowadays are made of plastic and modifications include a flexible part or even a spoon on one end. However, for environmental reasons, there is a move away from plastic and back to paper straws. Which takes more material to make, a 20 cm straw with a radius of 0.65 cm or a 21.5 cm straw with a diameter of 0.65 cm? Show your working.​