A disk of positive radius \(r\) in the Euclidean plane has area \(\pi r^2\). The same formula holds for a "disk" on the surface of a sphere if the radius is measured chordally in space! If your first thought is That can't be right, you're far from alone.
Created from high-quality wood, milled with simple clean lines and presented with a satin finish. Includes an off-white mount that will not discolour or fade with age. - Simple, elegant design - Premium, fine art paper with a gently textured surface - Handmade by specialist picture framers - FSC certified off-white mat / window mount - Delivered ready for hanging
