José Pablo Reyes 10 – 5
Square: multiply the base times its self Rectangle: multiply the base times the height (bxh) Triangle: multiply the base times the height time half (bxhx1/2) Parallelogram: multiply the base times the height (bxh)
Trapezoid: add the lenght of two parallel sides, then divide by 2 and multiply this by the height Kite: A=1/2xy Rhombus: ½(diagonal 2)(diagonal 1)
Composite figure: any figure/shape that can be divided into more than one basic figure. A figure that is made from two or more geometric figures Area of a composite figure: A=A1+A2
Area of a Circle: A= π (r²) Examples:
A solid is a three dimensional figure, it can me be made up of flat or curve surfaces. Face: any flat surface in the figure Edge: segment that is the intersection of two faces Vertex: point of intersection of 3 or more faces
Prism: 3D figure formed by two parallel congruent polygonal faces called bases, which are connected by faces that are parallelograms Net: a diagram of the surfaces of a 3D figure that can be folded to form the figure. A=2LW + 2(L+W)H
To find the surface area of a cylinder do de following; surface area of a cylinder = 2 π (r2) + 2 π (r)(h). Examples
Pyramid: 3D figure formed by a polygonal base and triangular faces that meet at a common vertex To find the surface area of a pyramid do the following; find the base area with b², once you know the base area and all faces are the same, do this: Base area + ½ x Perimeter x Slant lenght, if the faces are not the same do this, Base Area + lateral area Lateral area = all sides that are not the base Slant lenght = lenght of the segment, from the midpoint of the base to a vertex
To find the surface area of a cone; find the area of the circle, then turn the shape into its net. Add the measures up and thats the area of the cone.
To find the surface area of a cube do the following; find the surface area of one side and multiply it by 6. SA= 6(a²)
If two 3D figures have the same base are and same height, then they will have the same volume Examples
Prism: area of base X height Rectangular prism: L x W x H Cylinder: π (r²) add the area of the 2 faces, find the area of the bases using the formula A= π (r2), the combined surface area of the faces is 2 π (r2). Then find the surface area of the side which is circumference X height or 2 π (r)(h).
To find the volume of a pyramid use the following formula; 1/3 b(h) To find the volume of a cone use the following formula; 1/3 x π (r²)h
To find the surface area of a sphere you have to use this formula; 4 π (r²) To find the volume of a sphere use this formula; 4/3 π (r³)