BBC2 年
How to show the volume of a cone is ⅓ height × πr²
Image caption, Use the ruler to draw a line from the centre of the circle to the edge of the circle, then use the scissors to cut along the line. Image caption, Roll the circle into a cone ...
BBC6 年
How to prove a cone's surface area = π × r × slant length
Click to see a step-by-step slideshow. …to create a cone, use the ruler to draw two lines outwards from the centre point of the circle - both at slight angles as above. Use the scissors to cut ...