WhyNot Science on Instagram: "Why Surface Area of a Cone = πr(r + l) A cone’s surface has two parts — the circular base and the curved (lateral) surface. When you unwrap the lateral surface, it forms a sector of a circle. The radius of that sector is the slant height (l), and its arc length equals the circumference of the base (2πr). By rearranging that sector into a rectangle, its area becomes πrl. Adding the base area πr², we get the total surface area πr(r + l). ⚠️DISCLAIMER⚠️: This is not re