Geometry Portal

22_4_Solving_Right_Triangles

Now let's undo all that stuff you learned about right triangle trigonometry.

Lesson_Notes

Challenge_Problems

Challenge_Ans

SB_Ans_P316

SB_Ans_P318

Clinometer

Clinometer_Printout

Looking for an excuse to go outside to indirectly measure the height of a tree, a flagpole, a national monument? On a sturdy piece of paper, print and cut out this cheap but serviceable clinometer, put a weighted string through the indicated hole, and attach a drinking straw along the dotted line at the top of the diagram. The straw functions as your scope to focus your line of sight. For the weighted string, a metal washer tied to a string works well, just make sure your weight hangs below the edge of the paper. You are now ready to measure some angles of elevation.

Lesson_Vids

Intro, Part 1

Duration_4_27

Intro, Part 2

Duration_10_24

Intro, Part 3

Duration_14_22

Examples 5 and 6

Duration_14_34

Angle of Elevation and Depression

Crafts with Mr. Labelle! After explaining angles of elevation and depression, Mr. Labelle shows us how to construct a clinometer with some household items. Now go measure the height of that super tall tree in your neighborhood. Duration_9_26

Washington Monument

Mr. Labelle demonstrates how to properly use a cheap but serviceable clinometer to indirectly measure the height of the Washington Monument. Duration_8_42

Examples 7 and 8

Duration_3_18

Examples 9 and 10

Duration_3_35

TEKS

Geometry 7(B) apply the Angle-Angle criterion to verify similar triangles and apply the proportionality of the corresponding sides to solve problems.

Geometry 9(A) determine the lengths of sides and measures of angles in a right triangle by applying the trigonometric ratios sine, cosine, and tangent to solve problems

Geometry 9(B) apply the relationships in special right triangles 30º-60º-90º and 45º-45º-90º and the Pythagorean theorem, including Pythagorean triples, to solve problems

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