Understand Similar Figures

When are two geometric shapes considered similar? Choose the best answer.

• When their sides have the same length

• When their interior angles are the same and their sides are in proportion

• When they are extremely close in both shape and size

• When they have the same number of sides and angles

All ________________ triangles are similar.

• Equilateral

• Scalene

• Right

• Isosceles

A triangle has sides of 3 cm, 6 cm, and 8 cm. Which triangle has sides that are in the same proportion?

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A triangle has sides of 4, 10, and 12cm. This ratio can be simplified to:

• 1 : 2 : 3

• 1 : 7 : 9

• 2 : 8 : 10

• 2 : 5 : 6

You have two similar equilateral triangles. One has sides that measure 8 meters each; the other has sides of 40 cm each. What is the scale factor?

• 2 : 1

• 80 : 2

• 20 : 1

• 8 : 2

A square has sides of 5 cm each. Which square is similar?

• A square with sides of 4 cm each

• A square with sides of 10 cm each

• A square with sides of 5 meters each

• All of the above

What must you do in order to determine whether two rectangles are similar?

• Measure the interior angles of each rectangle

• Measure the sides of each rectangle to see if they're proportional

• Determine the scale ratio between the rectangles

• Divide the length of each side of the smaller rectangle by the length of each side of the larger rectangle

A tree casts a shadow of 3 meters, while a meter stick casts a shadow of 0.75 meters. How tall is the tree?

• 6 meters

• 5 meters

• 4 meters

• 3 meters

The short side of a rectangle is 6 cm, and the long side is 21 cm. Which of the following rectangles is similar?

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A rectangle has sides of 72 cm and 36 cm. Another rectangle has sides of 4 cm and 8 cm. What is the scale ratio?

• 9 : 1

• 8 : 1

• 7 : 2

• 5 : 3