Similar Triangles Review with Proportions

The pair of figures is similar. Find the missing side.

• x = 10

• x = 4

• x = 2

• x = 5

To find the height of a very tall pine tree, you place a mirror on the ground and stand where you can see the top of the pine tree.  How tall is the tree? Hint: the figures are similar triangles.

• 8 feet

• 72 feet

• 36 feet

• 144 feet

Solve for f.

• 6

• 4

• 3

• 8

Review the picture. Find the missing side measurement in the picture using a proportion.

• x = 900 m

• x = 52 m

• x = 25 m

• x = 0.04 m

In triangles ABC and DEF, angle B is congruent to angle E and angle C is congruent to angle F. If BC = 10 cm and EF = 20 cm, what is the ratio of the area of triangle ABC to triangle DEF?

• 1:2

• 1:4

• 2:1

• 4:1

Answer explanation

The ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding side lengths. Since EF:BC = 2:1, the ratio of the areas of triangle DEF to triangle ABC is 1:4.

Find missing side

• 5

• 7

• 9

• 11

Sides in similar figures must be proportional.  

• True

• False 

Two objects that are the same shape but not the same size are _______.

• Congruent

• Vertical

• Similar

• Complementary 

Solve for X.

• 2 ft

• 3 ft

• 4 ft

• 6 ft

Find y.

• 144

• 18

• 72

• 12