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Lesson 4

1. Lesson 4

1.6. Explore 3

Mathematics 20-2 M1 Lesson 4

Module 1: Trigonometry

 
Self-Check 2
 

Complete the following questions. It is very important that you show all of your work so your teacher can see how you solved the problem. You will have noticed that your answer may be slightly different depending on your solution method. If you don’t show your solution method, it is difficult to determine whether you understand how to solve multiple triangle problems.

 


text book
  1. Complete “Practising” question 9 on page 162 of your textbook. Answer

  2. A police helicopter uses a spotlight to look for suspicious activity at night. One particular night, the helicopter is flying 150 m above the ground and the diameter of the illuminated area is 100 m. Adrian is standing on the ground at the far end of the illuminated area and determines that the angle of elevation to the helicopter is 40°. Adrian has been asked to determine the angular width of the spotlight, marked by θ on the following diagram.

     

    This picture shows a helicopter and a large right triangle below it with one horizontal side, one vertical side, and the hypotenuse oriented diagonally from the ground to the helicopter. The vertical side is 150 m, and the bottom angle on the right is 40 degrees. An obtuse triangle is embedded in the right side of the right triangle. This second triangle shares the 40 degree angle with the right triangle. The bottom side is 100 m, and the top left angle is labelled as theta.

     

    Answer