Area and Perimeter
Scale Factor
Indirect Measurement
Similarity
Slope
100
What is the equation to find the perimeter of similar figures?
Perimeter A = Perimeter B * Scale Factor
100
What is scale factor?
It is the ratio which tells you how much smaller or bigger an object is than an original.
100
An example of an indirect measurement problem is a problem involving _________
Shadows
100
What things are the same between similar figures?
angle measures
100
Slope is a ratio which describes:
a)steepness
b)creepiness
c)sleepiness
a)steepness
200
What is the equation to find the area of similar figures?
Area A = Area B * (Scale factor)2
200
I have a rectangle with height 5. I make a dilated version with scale factor 4. What is the height of the new rectangle?
20 (4x5=20)
200
Manreet observes that a 1 foot tall flower casts a 2 foot long shadow. How long of a shadow would a 10 foot tree would cast?
20 ft
200
If two shapes are similar, their side lengths are related by what?
a ratio, also known as the scale factor
200
How do you calculate slope?
rise/run, change in y over change in x
300
A triangle has a side length of 3 inches and an area of 22 square inches. A similar triangle has a corresponding side length of 6 inches. Find the area of the larger triangle.
88 in2
300
You are making a scale model of the Empire State Building. If the Empire State Building is 1000 feet tall, what scale factor do I need to make a model with height 1 foot?
1/1000th.
300
Simran wants to find the unknown height of an object that casts a 25 foot shadow. She knows a similar object that is 5 foot tall casts a 10 foot shadow. What ratio could Simran use to find the missing height?
Lots of answers!
x / 5 = 25 / 10
5 / x = 10 / 25
300
What is the main difference between similarity and congruence?
Congruence means that shapes are exactly the same (sides and angles). Similarity means that shapes have sides related by SF and angles which are the same.
300
What is the slope of this line?
1/2
rise=3-0=3
run=8-2=6
slope = rise/run=3/6=1/2
400
A rectangle has a side length of 3 feet and an area of 24 square feet. A larger similar rectangle has a corresponding side length of 9 feet. Find the area of the larger rectangle.
216 ft2
400
I have a square with side lengths 5. I dilate it by scale factor 2 to make a new square. What are the perimeters of both squares?
20 (5+5+5+5=20)
40 (5x2=10, 10+10+10+10=40)
400
If a 25-foot-tall house casts a 75-foot shadow at the same time that a streetlight casts a 60-foot shadow, how tall is the streetlight?
20 ft
400
Which 3 transformations give congruence and which 1 gives similarity?
Congruence = translations, reflections, rotations
Similarity = dilations
400
What is the slope of this line?
1/2
rise=2-0=2
run=0-(-4)=4
slope = rise/run=2/4=1/2
500
Draw similar rectangles that are in the ratio of 2 to 3 . What is the ratio of the areas of the rectangles you drew?
4/9
500
I have a square with side lengths 5. I dilate it by a scale factor 2 to make a new square. What are the areas of both squares?
25 (5x5=25)
100 (5x2=10, 10x10=100)
500
The Gateway Arch in St. Louis, Missouri, is 630 feet tall. Suppose a 12-foot-tall pole that is near the Arch casts a 5-foot shadow. How long is the Arch’s shadow?
262.5 ft
500
Find X.
x=14
First find scale factor (16/24 = 2/3)
Then multiply SF by side corresponding to x.
500
Are triangles A,B, and C similar? Explain how you know.
They are similar. Proven by either:
1. AA
2. Similarity by dilation.
3. Similarity by having the same slope (same ratio of height to width).