1. Objective: To be able to use the formula for the Curved Surface Area of a Cone, alongside other mathematical topics

2. Starter Calculate the Area and Perimeter of this sector of a circle 6cm 220° Area of the sector: Perimeter of the sector: (Add on the 2 radii)

3. Curved Surface Area of a Cone Today we will see how to find the Surface Area of a Cone The base of a Cone is a circle which we have already seen how to work out The new part is the Curved Surface Area around the top… Base Curved Surface Area

4. Curved Surface Area of a Cone r l l θ Area of the sector: Base Circumference = 2πr 2πr2πr Circumference of the sector: The circumference of the base of the cone is equal to the arc length on the sector… (This sector is made by unfolding the curved area of the cone) C = 2πr Divide by 2π Multiply by 360 Divide by l Swap the ÷ 360 Replace θ from the previous equation Top x Top Bottom x Bottom Cancel the 360s and an l from top and bottom

5. Curved Surface Area of a Cone Curved Surface Area of a Cone = πrl r = the radius of the base of the Cone l = the length of the slope of the cone r l Objective: To be able to use the formula for the Curved Surface Area of a Cone, alongside other mathematical topics

6. Curved Surface Area of a Cone Calculate the Surface Area of this Cone 4cm 10cm Objective: To be able to use the formula for the Curved Surface Area of a Cone, alongside other mathematical topics

7. Curved Surface Area of a Cone Calculate the Curved Surface Area of this Cone 3cm 6cm You will need to use Pythagoras’ Theorem to find the slant height… Objective: To be able to use the formula for the Curved Surface Area of a Cone, alongside other mathematical topics

8. Plenary Curved SA of the Cone Curved SA of the Cylinder The Base In Total Objective: To be able to use the formula for the Curved Surface Area of a Cone, alongside other mathematical topics

9. Plenary

10. Summary We have learnt how to work out the Surface Area of a Cone We have seen where the formula comes from We have used it alongside other topics we have covered