Similar Triangles and Beginning Trigonometry

This is set up so that you can change one of the side lengths on a right angled triangle, or change one of the angles. Use the sliders in the top left. As you change one thing, watch what happens to the other sides and angles. This will help us start trigonometry: a new topic at Grade 7.
  • When the red angle is 30°, what is the link between the hypotenuse and the side opposite the red angle?
  • If the angle is 30° and the hypotenuse is 50, what is the opposite side?
  • Now try with the angle set at 45°, and at 60°. Can you spot any links between side lengths?