Agenda Friday, January 22

Homework 5 S&S p. 84 # 1 - 4

Problems 5.1 & 5.2 - using similarity to solve real world problems.

Daily Scribe?

What do you know about the rays of the sun and shadows?

the length of a shadow depends on the height of the object

shadows change their length for an object as the sun moves during the day

shadows are longer when the sun is near the horizon

shadows are shorter near the middle of the day

rays of the sun are parallel to each other at the same spot and at the same time of day

When might we want to use shadows to find out the height of an object?

Can you explain why each angle of the large triangle is congruent to the corresponding angle of the small triangle?

3 m

1.5 m8 m

x

Make a sketch of the building, stick and the shadows. Label each with the given measurement.

Use similar triangles to find the height of the building.

Sophia & Hannah use the mirror method to estimate the height of a traffic signal near their school. They make the following measurements:

·height from the ground to Sophia's eyes: 150 cm·distance from the middle of the mirror to Sophia's feet: 100 cm·distance from the middle of the mirror to a point directly under the traffic signal: 450 cm

Make a sketch. Show the similar triangles formed and label the given measurements.

Use similar triangles to find the height of the traffic signal.

Complete Problem 5.1 p. 79 part D and Problem 5.2 p. 81 part B.

You may work with your partner.

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