Final answer:
The correct formula for calculating the curved surface area of a cone is πrl, where r is the radius and l is the slant height. This corresponds to option (B). Significance in measurement dictates that the final answer must be rounded accordingly.
Step-by-step explanation:
Calculating the Curved Surface Area of a Cone
To find the curved surface area of a cone, you need to use the formula πrl, where π is Pi (approximately 3.1415927), r is the radius of the base of the cone, and l is the slant height of the cone. The correct option for calculating the curved surface area is therefore (B) Calculated as πrl. For example, if we have a cone with a radius (r) of 1.2 meters and we want to calculate the curved surface area, we would need the slant height (l) as well. Once both r and l are known, we multiply them together and then multiply by π to get the curved surface area. It's important to note that the number of significant figures in your measurement can affect the precision of your answer. If the radius is given to two significant figures, like 1.2 m, the final answer should be rounded to two significant figures as well.