Investigation 2: Practice Quiz
1. Which rectangles below are similar?
Explain why.
2. The triangles at the right are similar.
a. Use the side lengths of triangle R and the fact that the
triangles are similar to find the lengths of sides A and B and
the measure of angle )). In Triangle R angle )) is 90 degrees.
Side A=_______
Side B=_______
Angle ))=_______
b. What is the scale factor from triangle R to
triangle S?
c. What is the scale factor from triangle S to triangle R?
d. How many times greater is the perimeter of triangle R than that of triangle S?
e. How many times greater is the area of triangle R than that of triangle S?
3. Rectangle A is sketched here.
a. Rectangle M is similar to rectangle A. The scale factor from A to M is 2.
Draw and label rectangle M on the grid.
b. Rectangle T is similar to rectangle A. The scale factor from A to T is 3.
Draw and label rectangle T on the grid.
c. How does the scale factor of 2 change
the area and perimeter of rectangle A.
d. How does the scale factor of 3
change the area and side lengths of
rectangle A?
Investigation 2: Practice Quiz KEY
1. Which rectangles below are similar?They are all similar, on
the real quiz only 2 will be similar
Explain why.The scale factor for each is 2, multiply or divide all
sides by 2 to make another rectangle. NOTICE: B is turned on
its side.
2. The triangles at the right are similar.
a. Use the side lengths of triangle R and the fact
that the triangles are similar to find the lengths of
sides A and B and the measure of angle )). In
Triangle R angle )) is 90 degrees.
Side A=___5.6____The scale factor for the side
you can figure (8 to the 6.4) is divide by 1.25, use
this to find the missing sides
Side B=__4.8_____
Angle ))=__90_____
b. What is the scale factor from triangle R to triangle S?
SF: 6.4/8 = 0.8 or 8/10
c. What is the scale factor from triangle S to triangle R?
SF: 8/6.4 = 1.25 or 10/8 this is the reciprocal of the above question
d. How many times greater is the perimeter of triangle R than that of triangle S?
R: 21 perimeter S: 16.8 perimeter (need to use the answers from the sides above)
Answer: Triangle R is 1.25 times greater (16.8 x 1.25 = 21)
e. How many times greater is the area of triangle R than that of triangle S?
The area is 1.5625 times greater. Work: 1.25 x 1.25
remember the scale factor
3. Rectangle A is sketched here.
a. Rectangle M is similar to rectangle A. The scale factor from A to M is 2.
Draw and label rectangle M on the grid.
b. Rectangle T is similar to rectangle A. The scale factor from A to T is 3.
Draw and label rectangle T on the grid.
c. How does the scale factor of 2 change
the area and perimeter of rectangle A.
The area is 4 times larger
The Perimeter is 2 times larger
You need to be able to find the area and
The length should be 18 (6 x 3)
perimeter of both shapes
The width should be 12 (4 x 3)
d. How does the scale factor of 3
Put a A inside to label
change the area and side lengths of
rectangle A? The area is 9 times larger
The perimeter is 3 times larger. You
need to be able to find the area and
perimeter of both shapes.
is 1.25
The length
should be 12
(6 x 2)
The width
should be 8
(4 x 2)
Put a M
inside to
label