Understanding the triangle

• This part 1: • Power point for active learning method/ workshop.• In this power point children will experiment the concept of of sin

ratio.

Understanding the triangle

Part 1

Objectives• Making a right angle triangle.• Find the ratio of the sides of the triangle.• Measuring sin of the angle

Making a right angle• Take a A4 sheet. Cut into half pieces.• Take an half piece.

• Mark a point in the left bottom corner of the paper.• We will call this as origin

• Position the protector.

• Mark angle 30 degree.

• So we have a starting point.

• And we have another end point.

• Join these two points.

• Now we have a straight line at an angle 30 degree.

1

2

3

1

With adult supervision: Cut the paper as show in pictures 1,2,3.

• Take the triangle and mark the angle 30 degree in the corner where you have done your measurement.

• Measuring the triangle’s parameters:• Look for the 30 degree.• Measure it’s opposite side• Measure the adjacent side to 30 degree.• Measure the hypotenuse

Adjacent side

Opposite side

hypotenuse

30

33

Sample 1 Opposite side Adjacent side Hypotenuse

Note down the values in the table

• Now let us reduce the size of the triangle. Cut vertically to the base of the triangle.

Fill the second row

Sample 1 Opposite side Adjacent side Hypotenuse

1

2

• Again reduce the triangle size. Measure all three parameters of the triangle.

Fill A third row

Sample 1 Opposite side Adjacent side Hypotenuse

1

2

3

• Repeat the process until you get five rows.

What can you see in the table• As the adjacent side decreases, the opposite side and hypotenuse

decrease.

Break

Trigonometry• Trigonometry is a special and beautiful concept of maths.

• trigonon "triangle" + metron "measure”

• We are going to examine the triangle.

• Recall that our triangle has an angle 30 degree. We have an adjacent side, an opposite side and a hypotenuse.

Adjacent side

Opposite side

hypotenuse

30

Form the table• As the adjacent side decreases, the opposite side and hypotenuse

decrease.• Are you interested in

We are going to check a ratio

SINE Ratio

• We will call this as sine ratio.• Go back to the table of the right angle triangle with angle 30

Checking the Sine ratio for angle 30

Opposite side Adjacent side HypotenuseSide

Sin 30

1

2

3

4

5

Sin 30

Summary• We took a right angle triangle with an angle 30.• We measured opposite side and hypotenuses.• We found their ratio is constant. • Sine of an angle is the ratio of opposite side to that of hypotenuses.