1 / 16

Geometric Shapes and Formulas

Geometric Shapes and Formulas. Planes. A plane is a flat surface (think tabletop) that extends forever in all directions. It is a two-dimensional figure. Three non-collinear points determine a plane. So far, all of the geometry we’ve done in these lessons took place in a plane.

marli
Download Presentation

Geometric Shapes and Formulas

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Geometric Shapes and Formulas

  2. Planes • A plane is a flat surface (think tabletop) that extends forever in all directions. • It is a two-dimensional figure. • Three non-collinear points determine a plane. • So far, all of the geometry we’ve done in these lessons took place in a plane. • But objects in the real world are three-dimensional, so we will have to leave the plane and talk about objects like spheres, boxes, cones, and cylinders.

  3. Perimeter is the distance around a figure. • There are three ways to find the perimeter: • When the lengths of the sides are different, add the lengths of the sides. (S + S + S…=P) • When two pairs of sides are the same measurement, multiply 2 times the length and 2 times the width. Then add the products. (2xL) + (2xW)=P • When all the sides are the same length, multiply the number of sides times the length of one side. (SxL=P) • Ready for some problems?

  4. 2 L x W = units 2 3cm x 12cm = 36cm 3cm 12cm 7mm x 7mm = 49mm 2 7mm Area is the number of square units on a flat surface. To find the surface area of a quadrilateral use a formula.

  5. Different Names/Same idea • Length x Width = Area • Side x Side = Area • Base x Height = Area Free powerpoint template: www.brainybetty.com

  6. REAL formula for area of squares • Area= S^2 • Area= Side x Side (side squared) (just a different way of saying length x width) Side one Side two Free powerpoint template: www.brainybetty.com

  7. Parallelogram Area • Same idea as squares & rectangles, but they change the words to Base ( length: bottom of shape) and height (width) Free powerpoint template: www.brainybetty.com

  8. Parallelogram Area • Area=Base x Height • (Area=length x width) The diagonal line is NOT the height!!! 5 Height (width) 8 BASE (length) Base 8 x Height 5 = Area 40 Free powerpoint template: www.brainybetty.com

  9. Area of a Triangle • ½ Base x Height = Area • (It’s ½ because ½ of the “square” is missing) Height 5 Base 8 Height ½ Base x Height = Area ½ (8) x 5 = Area 4 x 5 = 20 Base Free powerpoint template: www.brainybetty.com

  10. Volume and Surface Area • The volume of a three-dimensional object measures the amount of “space” the object takes up. • Volume can be thought of as a capacity and units for volume include cubic centimeters cubic yards, and gallons. • The surface area of a three-dimensional object is, as the name suggests, the area of its surface.

  11. H W L Volume and Surface Area of a Box • The volume of a box is found by multiplying its three dimensions together: • The surface area of a box is found by adding the areas of its six rectangular faces. Since we already know how to find the area of a rectangle, no formula is necessary.

  12. 4 5 8 Example • Find the volume and surface area of the box shown. • The volume is • The surface area is

  13. Prisms • A prism is a three-dimensional solid with two congruent bases that lie in parallel planes, one directly above the other, and with edges connecting the corresponding vertices of the bases. • The bases can be any shape and the name of the prism is based on the name of the bases. • For example, the prism shown at right is a triangular prism. • The volume of a prism is found by multiplying the area of its base by its height. • The surface area of a prism is found by adding the areas of all of its polygonal faces including its bases.

  14. Pyramids • A pyramid is a three-dimensional solid with one polygonal base and with line segments connecting the vertices of the base to a single point somewhere above the base. • There are different kinds of pyramids depending on what shape the base is. To the right is a rectangular pyramid. • To find the volume of a pyramid, multiply one-third the area of its base by its height. • To find the surface area of a pyramid, add the areas of all of its faces.

  15. h r Cones • A cone is like a pyramid but with a circular base instead of a polygonal base. • The volume of a cone is one-third the area of its base times its height: • The surface area of a cone is:

  16. r Spheres • Sphere is the mathematical word for “ball.” It is the set of all points in space a fixed distance from a given point called the center of the sphere. • A sphere has a radius and diameter, just like a circle does. • The volume of a sphere is: • The surface area of a sphere is:

More Related