How to Calculate the Perimeter of a Semicircle

The Organic Chemistry Tutor

This instructional video provides a clear, step-by-step tutorial on calculating the perimeter of a semicircle. It addresses two distinct problem types: first, finding the perimeter when given the radius, and second, a more complex multi-step problem that requires finding the perimeter when given the area. The narrator breaks down the geometric components of a semicircle, explicitly distinguishing between the curved arc and the straight diameter. Key themes include geometric formulas, algebraic substitution, and logical problem-solving. The video emphasizes understanding the derivation of formulas rather than just memorizing them, showing how the perimeter of a semicircle is derived from the circumference of a full circle ($C = 2\pi r$) plus the diameter ($2r$). For educators, this video is valuable because it directly addresses a common student misconception: forgetting to include the diameter when calculating the perimeter of a semicircle. The step-by-step derivation and the inclusion of a "working backwards" problem (Area $\rightarrow$ Radius $\rightarrow$ Perimeter) make it excellent for scaffolding learning from basic geometry to intermediate algebraic applications.