BBC2 年
How to show a cone's surface area = π × r × slant length
to create a cone, use the ruler to draw two lines outwards ... Image caption, STEP 2: Unroll it and fold the shape in half vertically. Use a ruler to draw along the fold, then shade half of ...
BBC6 年
How to prove a cone's surface area = π × r × slant length
to create a cone, use the ruler to draw two lines outwards ... Image caption, STEP 2: Unroll it and fold the shape in half vertically. Use a ruler to draw along the fold, then shade half of ...