Indirect Measurement Using Similar Triangles

A tree is 12 feet tall and casts a shadow 9 feet long. A building nearby casts a shadow that measures 24 feet. How tall is the building? (Draw a picture, set up a proportion)

• 24 feet

• 21 feet

• 27 feet

• 32 feet

What is the scale factor from ΔDEF to ΔABC?

• 1/2

• 7/3

• 2

• 10/3

A triangle has sizes measuring 11 cm, 16 cm, and 16 cm. A similar triangle has sides measuring x cm, 24 cm, and 24 cm. What is x?

• x = 19 cm

• x = 24 cm

• x = 3 cm

• x = 16.5 cm

If the scale factor is 4, what is the measurement of slide length x?

• 21

• 1.25

• 20

A model of a house was built using the scale 5 in:25 ft. If a window in the model is 1.5 in. wide, how wide is the actual window?

• 90 ft

• 7.5 ft 

• 4.5 ft

• 45 in

What is the scale factor from the small fry to the large fry?

• 1/3

• 48

• 4

• 3

ΔABC∼ΔXYZ. Find the unknown measures.

• d = 25.5^o; z = 25 m

• d = 64.5^o; z = 9 m

• d = 64.5^o; z = 25 m

• d = 25.5^o; z = 9 m

Redon is 6 ft 2 in. tall, and his shadow is 4 ft 1 in. long. At the same time, a building casts a shadow that is 19 ft 10 in. long. What is the height of the building? Round to the nearest foot.

• 360 in

• 30 ft

• 2 ft

• 30 in

________________ figures are figures that have the same shape but not necessarily the same size.

• Congruent

• Similar

• Corresponding Angles

• Corresponding Sides

________________ is a method of using proportions to find an unknown length or distance in similar figures.

• Direct Measurement

• Corresponding Measurement

• Simlar

• Indirect Measurement