Surface & Lateral Area of Cones
How do you find the lateral area of cones?
Click the red point and drag down to view the net. Reset the figure and drag the red point down again. Observe how the lateral area of the cone can be flattened into a sector of a circle.
The flattened sector's radius is equal to the ______ _______ of the lateral area of the cone. The length of the arc of the sector is equal to the __________ of the circle created by the bottom of the lateral area of the cone.
Drag the straighten the arc slider, then click the dissect the sector box. Rearrange these small pie like pieces called sectors. You see that this forms a parallelogram or rectangle if you dissect the sector into many parts.
What is the formula to find the Lateral Area of a cone?
What is the formula to find the Surface Area of a cone?