SLIDE 1
DAY 157 – CIRCULAR BASED PRISMS
SLIDE 2 INTRODUCTION
So far, we understand what a prism is. Most important, we can see images inform of a prism in real life situation. For instance, most of our rooms are inform of a prism, more boxes for carrying goods are informed of a prism among others. We can identify this due to a uniform cross-section. In case a cross-section is a circle, would it qualify to be a prism? In this lesson, we are going to identify the shapes
- f two-dimensional cross-sections(circular sections)
- f three-dimensional objects.
SLIDE 3
VOCABULARY
Cross section A view of a figure when cut at any point along its length for objects with such features. Polygon A closed figure with 3 or more sides Prism A three dimensional object with a uniform cross section
SLIDE 4
Cone It is a pyramid whose base is a circle Prism It is a solid with a polygonal base which is also its cross section and rectangles along its height, or length.
SLIDE 5
Cylinder It is a solid with curved surface and a cross-section area that is a circle Sphere It is a solid whose shape is that of a ball. That is, all points on its surface are at equal distance from its center Pyramid It is a solid with a base and a curved or triangular surfaces along its height having a common apex.
SLIDE 6 Cylindrical prisms Prisms must have a uniform cross section throughout their length. This cross section can be any figure, whether a irregular or regular, polygonal or circular. So far, we have looked at a case where the cross section is polygon. If the cross section is circular, then we have only
- ne case, a circular based prism which is actually a
cylinder.
𝑠 𝑚
SLIDE 7
A cylinder is enclosed on sides by two circles that are equal and along its length/height by a curved surface which when cut along its length, we get a rectangle or a square whose radius is the length/height of the cylinder and length, the circumference of the circles at the end. When cut, we have the following image.
𝑠 𝑠 𝑚 2𝜌𝑠
SLIDE 8
Example Identify the number of circles that encloses a cylinder Solution The circle is the cross section of the cylinder hence it is at both ends of the figure. Hence, we have two equal circles
SLIDE 9
HOMEWORK When the curved surface of a cylinder is cut along a line parallel to its length, which figure(s) do we get?
SLIDE 10
ANSWERS TO HOMEWORK
rectangle or a square
SLIDE 11
THE END
