Equivalent Ratios
Scale Copies
Similar and congruent shapes
Definitions
Finding Slope
100
What does “n” equal?
1 : 2 = n : 4
n = 2
100
Are these two shapes scale copies? Why?
Yes, they are scaled copies. You can multiply the first rectangle by a scale factor of 3 to get the second rectangle.
100
True or false. Explain your answer.
All congruent shapes are similar.
True!
100
What is a Scale factor?
A scale factor is the number you multiply all sides of a shape by to make it bigger or smaller, while keeping the same shape.
100
Does the slope of a line stay constant?
Yes, the slope of a line stays constant.
200
What does “n” equal?
4 : 9 = 20 : n
n = 45
200
Are these two shapes scale copies? Why?
Yes, because you can multiply the first shape by 2 to get the other shape.
200
Are these shapes congruent?
Yes, they are congruent. They have the same side lengths and angles.
200
What is a Dilation?
the action of making a shape bigger or smaller
200
If two different lines have the same slope, what does that tell you about the lines?
It means the lines are parallel and never cross.
300
What does “n” equal?
2 : 3 = 1 : n
n = 1.5
300
What is the scale factor of the shapes below?
The scale factor is 1.5
300
Are these two shapes similar?
No, they do not have the same angles.
300
What does it mean for two shapes to be congruent?
Shapes that are both the same shape, same angles and exactly the same size.
300
What is the slope?
the slope is 1.
400
What does "n" equal?
2 : 5 = n : 13.75
n = 2.75
400
These two shapes ARE scaled copies. Find the missing red side.
the red side is 24cm
400
Are these two shapes similar? Why or why not?
No, they are not similar. There is not a number you can multiply to one shape to get the other.
400
What does it mean for two shapes to be similar?
If they have the same shape, same angles but not necessarily the same size (the sides must be proportional)
400
What is the slope?
the slope is 1/2
500
Are these two ratios equivalent?
20 pies : 44 cakes
14 pies : 26 cakes
No, they are not equivalent.
500
Which copy of the original triangle is NOT a scale copy? WHY?
Copy 3 is not a scaled copy of the original triangle. The shape has been distorted. The angles are different sizes and there is not one number we can multiply by each side length of the original triangle to get the corresponding side length in Copy 3.
500
These two shapes are similar, find the missing sides.
x = 15
y= 10
500
What is slope?
The slope of a line is the ratio of the amount that vertical y increases as horizontal x increases some amount.
Slope = Rise/Run or
Slope = Y2 - Y1/X2 - X1
500
Given the points (0,-1) and (2,3), what is the slope?
The slope is 4/2 or 2.