7/27/2019 Lesson Plan Trig Angles

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Lesson Planning S

Title: TrigonometryAngles

Learning Objectives:

By the end of the lesson:

All students should be able to use the Sine and Cosine function to calculate angles in right-angled triangles. Most students should be able to use the Sine, Cosine and Tangent function to calculate angles in right angled

triangles.

Some students should be able to calculate an angle in an isosceles triangle using Trigonometrical functions.Keywords: Trigonometry, Opposite, Adjacent, Hypotenuse, ArcTan, ArcCos, ArcSin

Learning Activities

Starter/Introduction

Students develop their problem solving skills by using Pythagoras theorem and trigonometric

functions to calculate the lengths in right-angled triangles. It is important for the class to sketch

their diagrams and label the edges in respect to the angle, i.e., Opposite, Adjacent and

Hypotenuse side.

Development

To calculate an angle in a triangle it isnecessary to first identify which

trigonometric function can be used. Use

the angle to label the sidesthe opposite

side is opposite the angle, the adjacent

side runs adjacent to it and the

hypotenuse is opposite the right angle.

In the base of the diagram to the right

both the Opposite and Adjacent are

known to therefore the Tangent function is

necessary since Sine and Cosine require

the hypotenuse side.

Explain that ArcTan, ArcSin and ArcCos are the opposite functions to Tan, Sin, and Cosrespectively. In a similar way to that plus is the opposite function to subtract and divide is the

opposite to multiply. Therefore, in the example above, by taking the ArcTan of both sides the Tan

function on the left hand side is cancelled. When demonstrating this to the class it is important to

provide a clear writing frame since multiple lines of working are needed.

Continue to work through the remaining examples on the second slide for consolidation. The

interactive Microsoft Excel file can be used to provide examples for the students to work from on

mini-whiteboards in order to assess their progress.

When ready students could progress through the problems on the third slide independently.

Feedback solutions throughout to maintain pace and challenge.

Plenary

The plenary is intended to both consolidate and extend the learning by having the class consider

an isosceles triangle rather than one that is right-angled. It may be necessary to guide the

students to create a right angled triangle by bisecting and halving the vertical distance. Have

the class attempt this on mini-whiteboards for assessment and feedback.

Resources:

Mini-

Whiteboard

Calculators

Interactive

Microsoft Exfile.

YouTube Vid

Differentiation

More able:

Students could consider right angled triangles within 3D grids.Less Able

Students may benefit from using only the sine and cosine function one lesson and move on to all threefunctions in the next.