Introduction
Hello future Mathematicians!
Let's take a journey to explore triangles and their angles.
Process
Task 1: Recap on acute angles
Step 1:
Watch the following youtube video.
Task 2: Obtuse Angles
Step 1: Extend the definition of trigonometric ratios.
Question 1:
What will cosine theta and sine theta be if the circle is of radius r instead?
Step 2:
Do the Investigation on page 175 in your textbook.
Question 2:
What can you conclude from the Investigation?
Step 3:
Look at the Conclusion tab for the answers of Question 1 and 2. Do Practise Now 1 and 2 in your notebook.
Step 4:
Give yourself a pat on the back. You have completed your elearning! :D
Conclusion
Question 1
Answer: cosine theta = x/r and sine theta = y/r
Question 2
Answer: sin A = sin (180-A) and cos A = -cos (180-A)