A scale is a comparison between the actual size of an object and the size of its diagram.
-It can be expressed as a ratio, a fraction, as a percent, in words or in a diagram
-The scale 1:32 means that 1 cm on the diagram represents 32 cm on the actual size
Ex. 1:18 means what?
*1 cm on diagram represents 18 cm on real object
Scale diagram - is a drawing that is similar to the actual figure or object
-May be smaller or larger than the actual object, but must be in the same proportions
Proportion - Is a relationship that shows ratios are equal. It can be written in fraction or ratio form.
Ex. The ratio 1 girl to 4 students is the same as 5 girls to 20 students.
As a proportion write:
1/4 = 5/20 OR* 1:4 = 5:20
Ex. 1/16 = 4/64 OR* 1:16 = 4:64
-It can be expressed as a ratio, a fraction, as a percent, in words or in a diagram
-The scale 1:32 means that 1 cm on the diagram represents 32 cm on the actual size
Ex. 1:18 means what?
*1 cm on diagram represents 18 cm on real object
Scale diagram - is a drawing that is similar to the actual figure or object
-May be smaller or larger than the actual object, but must be in the same proportions
Proportion - Is a relationship that shows ratios are equal. It can be written in fraction or ratio form.
Ex. The ratio 1 girl to 4 students is the same as 5 girls to 20 students.
As a proportion write:
1/4 = 5/20 OR* 1:4 = 5:20
Ex. 1/16 = 4/64 OR* 1:16 = 4:64
Enlargements and reductions
An Enlargement is an increase in the dimensions of an object by a constant factor
It can be 3-D or 2-D
For example, each dimension of this enlargement is twice the length of the
A reduction is a decrease in the dimensions of an object by a constant factor
Can be 2-D or 3-D
Each dimension of this reduction is half the length of the original
It can be 3-D or 2-D
For example, each dimension of this enlargement is twice the length of the
A reduction is a decrease in the dimensions of an object by a constant factor
Can be 2-D or 3-D
Each dimension of this reduction is half the length of the original
Scale factor - The constant factor by which all dimensions of an object are enlarged or reduced in a scale drawing
Notes
-An enlargement results in an image that is the same shape but proportionally larger than the original
-A reduction results in an image that is the same shape but proportionally smaller than the original
-The scale factor is the constant amount that all dimensions of an object are multiplied by to draw an enlargement or reduction
-A scale factor greater than 1 indicates an enlargement
-A scale factor less than 1 indicates a reduction
-You can use grid paper and a scale factor to draw enlargements and reductions
-An enlargement results in an image that is the same shape but proportionally larger than the original
-A reduction results in an image that is the same shape but proportionally smaller than the original
-The scale factor is the constant amount that all dimensions of an object are multiplied by to draw an enlargement or reduction
-A scale factor greater than 1 indicates an enlargement
-A scale factor less than 1 indicates a reduction
-You can use grid paper and a scale factor to draw enlargements and reductions
Corresponding angles and corresponding sides
-Have the same relative position in geometric figures
<A and <D Corresponding angles:
<B and <E
<C and <F
Corresponding sides:
AB and DE
BC and EF
AC and DF
-Have the same relative position in geometric figures
<A and <D Corresponding angles:
<B and <E
<C and <F
Corresponding sides:
AB and DE
BC and EF
AC and DF
Similar polygons
Polygon: A two dimensional closed figure made of three or more line segments
Polygon: A two dimensional closed figure made of three or more line segments