# ACTIVITY 2 - HOW TALL IS… ? Tuesday November 30th, 2010 Rollie Comeau Watson Lake Secondary School.

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ACTIVITY 2 - HOW TALL IS… ? Tuesday November 30th, 2010 Rollie Comeau Watson Lake Secondary School

ACTIVITY 2 How tall is …? Specific Outcomes A.3 - 3.1 and 3.2 B.2 - 2.3 and 2.7 B.3 - 3.5, 3.6 and 3.7 B.4 - 4.1 and 4.2 B.5 - 5.1, 5.4, 5.7, and 5.8

ACTIVITY 2 How tall is …? Material needed: ProtractorTube (one foot long) TapeString WeightPencil PaperCalculator Warm Clothing

ACTIVITY 2 How tall is …? Problem You need to cross a particularly swift creek. It is too wide to jump. A tree stands close to the edge of the creek. How can you determine if the tree is long enough to safely span the creek?

ACTIVITY 2 How tall is …? Tree Ground Distance

ACTIVITY 2 How tall is …? To solve this problem, the concepts of similar triangles, right-triangles, trigonometry, parallel lines and transversal lines, and/or referents can be introduced in your lesson.

ACTIVITY 2 How tall is …? Lets use trigonometry to solve this problem. The three basic trigonometric ratios involve two sides of a right-triangle and one of the two acute angles.

ACTIVITY 2 How tall is …? In our case, we are looking for the height of the tree - this is the unknown value we are seeking.

ACTIVITY 2 How tall is …? The distance from the tree can be assessed with the help of a long measuring tape. This is one of our known values. We are missing an acute angle…

ACTIVITY 2 How tall is …? From the ground, looking up at the top of the tree, we could possibly determine the angle of elevation. For this, you will need to consult a surveyor who can measure it for you or, construct a simple device that can do it for you!

ACTIVITY 2 How tall is …? A simple clinometer comes to mind… lets construct one!

ACTIVITY 2 How tall is …? Before going outdoors, you will need to determine the height of your eyesight. For convenience, a measuring tape has been placed on the wall to assist you. Record this value on the Activity 2 data sheet provided.

ACTIVITY 2 How tall is …? As a group, select a set distance from the object to be measured. Record this value as Ground Distance.

ACTIVITY 2 How tall is …? Each member of the team should: a)Use the clinometer (viewing through the tube at the top of the tree) b)Take the reading off the clinometer (angle in degrees) c)Record the measurement read by b)

ACTIVITY 2 How tall is …? Upon return, a)Draw a diagram representing the problem we are attempting to solve b)Place all measurements in the diagram c)Use trigonometry to solve the problem