Trigonometry Revision

Trigonometry Revision

Recall what trigonometric ratios mean

• sine

• cosine

• tangent

Poll

Determine the sine of 60 degrees.

• 0.33

• 0.866

• -1.2

• 0.79

Poll

Find the height of an isosceles triangle whose base angles are 25 degrees and whose base is 6 cm.

• 1.40 cm

• 8.01 cm

• 2.80 cm

Poll

Find the acute angles of the right triangle with side 5 cm and hypotenuse 10 cm.

• 45 and 45 degrees

• 40 and 50 degrees

• 30 and 60 degrees

Recall the sine rule

Remember it works for ANY triangle.

Poll

The angle opposite a 20 cm side of a triangle is  $88\degree$  . Find the angle opposite its 12 cm side!

• 42.9 degrees
  

• 36.8 degrees
  

• 22.0 degrees
  

Recall the cosine rule

Remember it can be used for ANY triangle.

Poll

Two sides of a triangle are 15 cm and 28 cm, the angle between them is 112 degrees. Find the missing side of the triangle.

• 31.1 cm

• 22 cm

• 36.4 cm

The area of ANY triangle

Poll

Two sides of a triangle are 12 cm and 20 cm. The angles opposite these sides are 40 and 80 degrees, respectively. Find the area of the triangle.

• 104 cm²

• 208 cm²

• 312 cm²