1. Triangle

2. Star

3. Cone

Explain why when you cut the curved surface of the right circular cone and flatten it into two-dimension, you expect to get a sector (a sector is part of a circle like a shape of a pie of a pie chart).
Hence, show that the area of the curved surface of the right circular cone can be expressed as A=πrl, where r is the base radius of the cone, l is the length of the curved surface of the cone.
luv,
ms ang